Search engine optimisation (SEO) is the work of helping your website show up when people search for what you offer. Done well, it turns Google into a steady, compounding source of customers who are already looking to buy.

This guide is the plain-English starting point. It explains what SEO actually is, how search engines decide what to rank, the three things that move the needle, and where to begin. Each section links to a deeper guide if you want to go further.

What SEO actually means

When someone types a question into Google, the search engine sorts through billions of pages in a fraction of a second and ranks the ones it thinks are most useful. SEO is everything you do to become one of those useful, trusted answers.

The key difference from advertising: with paid ads the traffic stops the moment you stop paying. With SEO, a page that earns its ranking keeps bringing in visitors for months or years. That is why SEO compounds, and why it is worth doing properly. If you want the full business case, see why SEO is important for your business.

How search engines decide what to rank

Google weighs up hundreds of signals, but they boil down to three questions:

  1. Can we find and read this page? If a search engine cannot crawl and understand your site, it cannot rank it. This is the technical side.
  2. Does this page answer the search? The content has to genuinely match what the person is looking for, in the right depth.
  3. Can we trust this site? Links from other reputable sites, consistent listings and real reviews all tell Google your business is credible.

Get all three pointing in the same direction and you have the foundations of a page that ranks.

The three pillars of SEO

Almost everything in SEO sits under one of three headings. A healthy strategy gives attention to all three rather than obsessing over one.

1. Technical SEO

This is the foundation: site speed, mobile friendliness, a clean site structure, secure pages and the behind-the-scenes signals that let search engines crawl and understand your content. Get this wrong and your best content struggles to rank. Our guide to technical SEO breaks down the parts that matter most.

2. Content

Content is how you answer the searches your customers are making. That means having the right pages for the right terms, written to be genuinely useful rather than stuffed with keywords. It starts with understanding what people actually type, which is the job of keyword research.

3. Authority

Authority is your reputation in Google’s eyes. Earned links from credible websites, consistent local listings and genuine reviews all signal that your business can be trusted. Authority is usually the slowest pillar to build and the hardest for competitors to copy, which is exactly what makes it valuable.

The main types of SEO

You will often see SEO split into a few overlapping types. They are useful labels for where to focus:

  • On-page SEO: optimising individual pages, from the content and headings to the page title. (You can sanity-check your titles with our free meta title length checker.)
  • Off-page SEO: building reputation and links beyond your own site.
  • Technical SEO: the crawlability and performance foundations covered above.
  • Local SEO: getting found by people searching in your area, plus the Google map pack. If you serve a town, city or region, read what local SEO is and how it works.

SEO and the rise of AI search

More people now ask tools like Google AI Overviews, ChatGPT and Perplexity instead of scrolling a list of blue links. Getting cited in those answers is a newer discipline called Generative Engine Optimisation (GEO), and it rewards the same fundamentals: clear, well-structured, trustworthy content.

It is not a replacement for SEO, it is an extension of it. The brands investing early are building an advantage their competitors have not noticed yet. Our guide to AI SEO and GEO explains how to get your brand into AI answers.

How long does SEO take?

SEO is a medium-term play, not an overnight switch. Most businesses see early movement within a few months, with momentum building from there as content matures and authority grows. Competitive terms in established industries take longer. Anyone promising page one in a fortnight is best avoided.

How to get started

You do not need to do everything at once. A sensible order for a beginner:

  1. Run a health check. See where you stand before you change anything. Here is how to do an SEO audit, step by step.
  2. Fix the technical basics. Make sure your site is fast, mobile friendly and crawlable.
  3. Get the keywords right. Map your important pages to the terms people actually search.
  4. Make every key page genuinely useful. Answer one clear search intent per page, with a unique title.
  5. Build a little authority. Earn a few quality links, claim your listings and gather reviews.

That is the whole game in five steps. The detail is where the work lives, but the direction is simple.

Common SEO terms, decoded

A few words you will meet everywhere, in plain English:

  • SERP: the search engine results page, the list you see after searching.
  • Keyword: a word or phrase people search for, and that you target with a page.
  • Backlink: a link from another website to yours, a key trust signal.
  • Crawling and indexing: how search engines discover (crawl) and store (index) your pages.
  • On-page vs off-page: work done on your own site versus reputation built elsewhere.
  • SEO vs SEM vs PPC: SEM (search engine marketing) is the umbrella; SEO is the organic side, PPC (pay-per-click) is the paid ads side.

Quick questions

Is SEO free? The clicks are free, the work is not. You are investing time or money into content, fixes and authority rather than paying per click as you would with ads. If you’re wondering what that investment looks like, see our guide to how much SEO costs in the UK.

How long until I see results? Usually a few months for early movement, longer in competitive markets. It builds rather than switches on.

Can I do SEO myself? The basics, yes, especially using this cluster of guides. Competitive industries and technical fixes are where a specialist earns their keep.

Does SEO still matter with AI search? Yes. AI answers draw from the same trustworthy sites that rank well, so strong SEO increasingly feeds AI visibility too.

Where to go next

If you would rather have a specialist team handle it, take a look at our SEO services or get a free SEO audit and we will show you exactly where your biggest opportunities are.