On Site SEO
On-site SEO is the set of changes you make directly on a website’s pages and HTML to help search engines understand the content and users navigate it better.
If you have ever optimised a page and still failed to rank, you already know that on-site SEO is necessary but not sufficient without off-page signals like backlinks.
Key points
- Write title tags and headings that describe the page topic and intent, not generic phrases.
- Use keywords naturally in content; stuffing them harms readability and relevance.
- Add internal links to help users and search systems discover related pages.
- Optimise images with descriptive alt text and filenames for accessibility and context.
- Check page speed and mobile layout as part of every on-site optimisation checklist.
- Review your pages against current Google Search Central guidance, not a fixed checklist.
A product page that ranks after on-site fixes
A small ecommerce site sold camping stoves. The page had a vague title tag 'Stove – Shop', no heading tags, and a single image with no alt text. After changing the title to 'Lightweight Camping Stove – 2-Burner Portable Gas Cooker', adding H1 and H2 headings that matched search intent, writing alt text for the image, and adding internal links from three related blog posts, the page moved from page 5 to page 2 for 'camping stove' over eight weeks. No backlinks were added, so off page seo techniques were not involved.
Three things on-site SEO is not
- Not off-page SEO On-site SEO controls what you put on your pages; off-page SEO builds authority through backlinks and brand mentions from other sites. Off site seo services focus on external signals.
- Not a one-time fix Google updates title rewrites, structured data handling, and ranking systems, so page elements need periodic review against current guidance.
- Not just content Technical elements like page speed, indexability, and structured data are part of on-site optimisation, not separate from it. On page seo vs technical seo is a false distinction.
Four common mistakes and how to avoid them
- Keyword stuffing Writing the same keyword repeatedly in content hurts readability and can trigger spam filters. Write naturally for search intent instead.
- Duplicate title tags Using the same title tag on multiple pages confuses search engines about which page is relevant. Write unique, descriptive titles for each page.
- Ignoring internal linking Without internal links, search systems struggle to discover related pages and understand site structure. Link between topical pages.
- Skipping technical elements Treating on-site SEO as only content work misses speed, indexability, and structured data. These affect both ranking and user experience.
Three ways on-site SEO overlaps with technical SEO
- Page speed Core Web Vitals like LCP and INP are measured at the page level and are part of on-site optimisation checklists, not just technical SEO.
- Structured data Adding schema markup to a page helps search engines understand its content and can enable rich results. This is an on-site task.
- Alternative terminology Onpage SEO is a common alternative label for on-site SEO, though some practitioners use it to refer only to content changes, excluding technical aspects like speed.
Common questions
What is SEO and how does it work?
SEO stands for search engine optimisation. It works by making pages more relevant and authoritative for specific search queries through on-site and off-site changes.
What are the best on-page SEO tools?
Common tools include Google Search Console for performance data, Screaming Frog for crawling, and Ahrefs or Semrush for keyword and content analysis.
Sources
- Google Search Central: SEO Starter Guide Covers on-site elements like title tags, headings, and internal links.
- Google Search Central: Create helpful, reliable, people-first content Guidance on writing content that aligns with search intent.
- Google Search Central: Structured data How to add structured data as part of on-site optimisation.