SEO Basics
SEO stands for search engine optimisation. It is the practice of making a website more visible in search results, so people can find it without you paying for each visit.
What is SEO?
When someone searches on Google, the engine decides which pages to show and in what order. That decision is based on hundreds of signals: how relevant the content is to the query, how trustworthy the site appears, how fast and usable the pages are, and how many reputable sites link to them. SEO is the discipline of understanding those signals and improving them.
The goal is to earn unpaid, or organic, positions in search results. Organic results sit below any paid adverts and get the majority of clicks. Unlike paid search, where visibility stops the moment a campaign ends, organic rankings built through SEO continue to drive traffic as long as the content stays relevant.
What SEO is not
SEO is not about tricking search engines. The tactics that gamed early algorithms have been closed off over time. What remains is more straightforward: create genuinely useful content, ensure the site is technically sound, and build a reputation worth citing.
It is also not a one-time fix. Search engines update their algorithms regularly, competitors improve their own sites, and what people search for shifts over time. SEO is an ongoing activity, not a project with an end date.
The four types of SEO
SEO splits into four main disciplines:
- On-page SEO covers the content and signals on each page: title tags, headings, the depth and accuracy of the writing, internal links, and structured data.
- Technical SEO covers the infrastructure of the site: how quickly pages load, whether search engines can crawl and index everything, mobile usability, and site architecture.
- Off-page SEO covers what the rest of the internet says about the site, primarily through links from other websites, which act as votes of confidence.
- Local SEO covers visibility for businesses that serve a specific geography, including Google Business Profile, local pack rankings, and citations.
A fifth area has emerged alongside these: optimising for AI-powered answer engines. AI search retrieves and cites content differently from traditional results pages, and the signals that earn citations there overlap significantly with good SEO practice.
Where to start
If you are new to SEO, these pages cover the foundational concepts before the detail of each discipline:
In this guide
- How Search Engines Work
How Google and other search engines discover, store, and rank web pages. A plain-English explanation of crawling, indexing, and ranking.
- What Is Organic Search?
What organic search results are, how they differ from paid ads, and why organic visibility matters for long-term traffic.
- Types of SEO Explained
A plain-English guide to the main types of SEO: on-page, technical, off-page, local, and AI search optimisation, and what each one covers.
- How Long Does SEO Take?
Realistic SEO timelines, why results take months rather than weeks, and the factors that affect how quickly a site sees improvement.
- How to Measure SEO Performance
The key metrics and tools for tracking SEO progress: what to look at in Google Search Console and GA4, and how to interpret the numbers.