What is SEO? A simple, complete guide for beginners

SEO (search engine optimization) is the practice of improving a website so it shows up in the free, unpaid results of search engines like Google and Bing, and today in AI answers from tools like ChatGPT, Perplexity and Google’s AI Overviews. It works on three fronts: the content on your pages (on-page SEO), the technical health of your site (technical SEO), and the trust your site earns from other websites, such as links and mentions (off-page SEO).

I’m Ana Carolina Gomes, an SEO specialist who has worked in off-page SEO, link building and digital PR since 2023. In this beginner’s guide to SEO, I explain every basic part in plain words, with real examples from my own work.

In this guide, you’ll learn:

• What SEO means and why it matters
• How search engines find, understand and rank pages
• The three types of SEO: on-page, technical and off-page
• How keywords and search intent work
• What E-E-A-T is and why Google cares about it
• The difference between SEO and GEO (optimizing for AI answers)
• How long SEO takes and how to measure results

Key takeaways

• SEO helps your website appear in free search results and in AI answers.
• It rests on three pillars: helpful content, a healthy website and trust from other sites.
• Matching search intent matters more than repeating keywords.
• Results usually take three to six months, and the work never really stops.
• GEO builds on SEO: the same clear, trustworthy content helps you rank and get cited by AI.

What does SEO mean, and why does it matter?

SEO stands for search engine optimization. In simple terms, it means making your website easier to find, easier to understand and more trustworthy for both people and search engines.

It matters because search is where most online journeys start. When someone types “best running shoes for flat feet” or “how to fix a leaking tap”, they already have a need. SEO puts your page in front of them at that exact moment.

There are three big reasons businesses invest in SEO:

• The traffic is free per click. You don’t pay Google when someone clicks an organic result. SEO still costs time and work, but the results don’t stop the day you stop paying, like ads do.
• The visitors are interested. People who find you through search are actively looking for what you offer, so they are more likely to read, sign up or buy.
• It builds trust. Pages that rank well, and that AI tools quote, look more credible to readers.

SEO is also different from paid search (PPC). With PPC, you pay for every click on an ad. With SEO, you earn your place in the results. Together, they make up search engine marketing (SEM).

How do search engines like Google work?

Search engines work in four steps: they crawl the web to find pages, render them, store them in an index, and rank them when someone searches. If any step fails, the page won’t show up, no matter how good it is.

• Crawling. Programs called crawlers (or bots) visit the web and follow links from page to page to discover new content. They also read your XML sitemap, a file that lists the pages you want them to find.
• Rendering. The search engine loads the page’s code (HTML, CSS and JavaScript) to see it the way a visitor would.
• Indexing. The search engine analyzes the page and decides whether to store it in its index, a giant library of web pages. Not every page gets in. Thin or duplicate pages are often left out.
• Ranking. When someone searches, the engine picks the most relevant, useful and trustworthy pages from its index and puts them in order.

A simple way to remember it: first Google has to find your page, then understand it, then trust it.

Google isn’t the only engine that matters. Bing powers its own results and also feeds several AI search tools, so it’s worth checking your site in Bing Webmaster Tools as well as Google Search Console. Both are free.

What are the main types of SEO?

SEO has three core types, plus a few specialties. Think of it like a sports team: technical SEO is your defense, on-page SEO is your offense, and off-page SEO is the fans who cheer for you.

On top of these, there are specialties such as local SEO (showing up in Google Maps and “near me” searches), e-commerce SEO (online stores), international SEO (sites in several languages or countries) and, more recently, GEO (visibility in AI answers). The next sections explain each core type in more detail.

What are keywords and search intent?

Keywords are the words people type (or say) into a search engine. Search intent is the reason behind those words: what the person actually wants to get done.

Keyword research means finding the terms your audience uses, how many people search for them, and how hard it is to rank for them. Free tools like Google Search Console and Google Keyword Planner are a good place to start.

But the words alone are not enough. You need to match the intent. There are four common types:

A quick tip: search your keyword on Google and look at the top results. If they are all guides, write a guide. If they are all product pages, a blog post probably won’t rank.

What is on-page SEO?

On-page SEO is everything you do on the page itself to make it useful for readers and clear for search engines. It’s the part you control the most.

The main elements are:

• Title tag: the clickable blue headline in Google. Put your main keyword near the start and make a clear promise, like “What is SEO? A simple guide for beginners”.
• Meta description: the short summary under the title. It doesn’t affect ranking directly, but a good one gets more clicks. Start with an action word such as “learn” or “discover”.
• Headings (H1, H2, H3): they organize the page so readers can scan it. Question-style headings, like the ones in this post, also match how people search and how they ask AI tools.
• Keyword placement: use your main keyword naturally in the first paragraph, in at least one heading, in the body and in the last paragraph. Use synonyms instead of repeating the same phrase. Keyword stuffing makes text hard to read and can hurt rankings.
• Content quality: original, accurate, up to date and more helpful than what already ranks.
• Links: internal links point to related pages on your own site; external links point to trustworthy sources that back up your claims. Both help readers and show search engines how topics connect.
• Images: rename files before uploading (what-is-seo-diagram.jpg, not IMG_4021.jpg), compress them so pages load fast, and add alt text that describes the image for search engines and screen readers.
• Short, clean URLs: use the keyword and skip dates, for example /blog/what-is-seo instead of /page?id=12345 or /what-is-seo-2026.

I practiced all of these in my capstone project for the SEO Mastery specialization, where I built an SEO plan for a brand called GreenSip. You can see the full process, from keyword research to page structure, in the GreenSip case study.

What is technical SEO?

Technical SEO makes sure search engines can find, load and understand your site without problems. Great content can’t rank if Google can’t reach it.

The basics to check are:

• Crawlability: important pages are linked from somewhere and not blocked by your robots.txt file.
• Indexing: you have an XML sitemap, and you use canonical tags to tell Google which version of a page is the main one.
• Site speed: pages load fast. Google measures this with Core Web Vitals.
• Mobile-friendliness: the site works well on phones, because Google looks at the mobile version first.
• Security: the site uses HTTPS (the padlock in the browser bar).
• Structured data (schema): extra code that labels your content. For a blog post, the most useful types are Article, FAQPage and Person (the author). It helps search engines and AI tools understand who wrote the page and what it covers.
• Site structure: a logical menu where important pages are only a few clicks from the home page.

You don’t need to be a developer to start. Google Search Console, which is free, shows which pages are indexed and flags most technical errors.

When you publish a new page, you can also ask Google and Bing to index it straight away with the URL inspection tools in Search Console and Bing Webmaster Tools. For the official rules, Google’s SEO Starter Guide and Search Essentials are the best places to start.

What is off-page SEO and link building?

Off-page SEO is everything that happens outside your website to build its reputation. The biggest part is link building: getting other trusted websites to link to yours. Each link works like a vote of confidence.

Not all links are equal. One link from a respected news site is worth more than dozens from random, low-quality sites. Off-page SEO also includes brand mentions, online reviews and digital PR, which means creating stories or data that journalists want to cover.

This is the area I work in every day. One real lesson: link building at scale is mostly about process, not luck. Each campaign needs a brief that explains the target page, the right anchor text and, in regulated markets, the legal rules for each country.

Writing those briefs by hand was slow and easy to get wrong. So I built a pilot workflow with Claude Code and Python that creates the briefs automatically and applies each country’s compliance rules. In a pilot covering the UK and Spain, the workflow turned a simple spreadsheet into complete briefs, with title, H2/H3 outline and verified sources, while keeping the exact anchors and target URLs. It also caught something nobody had noticed: some of the disclaimers in our existing template were already out of date.

The takeaway for beginners: good off-page SEO is about earning links people would want to give you anyway, and building a system so you can do it consistently.

What is E-E-A-T, and why does Google care about it?

E-E-A-T stands for experience, expertise, authoritativeness and trustworthiness. It’s the set of qualities Google uses to judge whether content is reliable. It isn’t a single ranking factor, but it shapes how Google’s systems and human quality raters see your pages.

• Experience: have you actually done what you’re writing about? First-hand examples, photos and real numbers show this.
• Expertise: do you have the knowledge or skills to talk about the topic?
• Authoritativeness: do other trusted sites and people recognize you or your brand?
• Trustworthiness: is the content accurate, honest and safe? Trust is the most important of the four.

This is why this post includes my own work instead of only general definitions. Anyone can repeat what SEO is. Sharing what happened when you did it is what makes content worth trusting, for Google and for AI tools.

What is the difference between SEO and GEO?

SEO helps your pages rank in search results. GEO (generative engine optimization) helps your content get quoted or recommended in AI-generated answers, such as Google’s AI Overviews, ChatGPT, Gemini, Copilot and Perplexity.

GEO doesn’t replace SEO. It builds on it. AI tools often pull from pages that already rank well and come from trusted sources. Google’s AI Overviews now appear in a large share of searches (Search Engine Land covers this shift well), so being the source an AI quotes matters more every year.

The good news: the same habits help both. To make your content easy for AI tools to understand and quote:

• Answer first. Put the direct answer in the first sentence under each heading, then explain.
• Think in prompts, not just keywords. People ask AI full questions, like “what’s the difference between SEO and GEO?”. Use those questions as headings.
• Make it scannable. Short paragraphs, lists, tables and a key takeaways box are easy for both people and AI to pull from.
• Show who’s behind it. A named author, a visible “last updated” date and links to credible sources are strong trust signals.
• Add schema. Article, FAQPage and Person markup give AI tools a structured summary of the page.
• Test your questions. Ask ChatGPT, Perplexity or Gemini the questions you want to answer and see which sources they cite today. That shows you the bar to beat.

How long does SEO take, and how do you measure it?

Most sites see early signs of progress within a few weeks, but meaningful results usually take three to six months. Competitive keywords can take a year or more. SEO is never “done”: search engines, competitors and your own site keep changing.

To know if it’s working, track a mix of metrics:

Compare each month with the same month last year when you can. It avoids reading normal seasonal dips as problems.

How do you start doing SEO?

The best way to learn SEO is to practice on a real page. SEO is simply the work of making your site easy to find, easy to understand and worth trusting for search engines, for AI tools and, above all, for people.

A simple first-week plan:

• Set up Google Search Console and Bing Webmaster Tools for your site.
• Pick one topic and look at what people search for, including the “People also ask” questions on Google.
• Write one page that answers the main question in the first paragraph and covers the follow-up questions under clear headings.
• Check the basics: title tag, meta description, headings, image names and alt text, internal and external links.
• Ask ChatGPT or Perplexity the same question and compare your page with the sources they cite.

I’m following these same steps on this site. To see them applied to a full project, from keyword research to page structure, read my GreenSip case study.

FAQ

Is SEO free?

You don’t pay for organic clicks, but SEO takes time, skills and sometimes tools or an agency. Think of it as an investment, not a free channel.

Can I do SEO myself?

Yes. Start with free tools like Google Search Console, learn the basics in this guide, and practice on your own website or blog.

Is SEO dead because of AI?

No. Most people still use search engines every month, and AI tools often rely on pages that already rank well. SEO is changing, not disappearing.

How do I get my content cited by ChatGPT or Google’s AI Overviews?

There’s no switch to flip, but the basics help: answer questions directly, use clear question-style headings, cite credible sources, show who wrote the page, add schema and build a brand that other trusted sites mention.

What’s the difference between SEO and SEM?

SEM (search engine marketing) is the umbrella term. It includes SEO, which earns free results, and PPC, which pays for ads in search results.

What should I learn first?

Search intent and keyword research. If you understand what people want when they search, every other part of SEO gets easier.

Sources

• Search Engine Land: What is SEO? Search engine optimization
• Digital Marketing Institute: What is SEO and how does it work?
• Google Search Central: SEO Starter Guide
• Reply: The new search: how to master generative engine optimization
• Geeky Tech: GEO in different content types: blogs, guides, docs
• Bynder: 12 tips for writing SEO-optimized content