On-page SEO checklist
| Element | Best practice |
|---|---|
| Title tag | Main keyword near the start, unique per page, about 50 to 60 characters (Google truncates by pixel width, roughly 600px) |
| Meta description | About 150 to 160 characters, a clear benefit and a reason to click. Not a ranking factor, but it affects clicks |
| H1 | One per page, describing the topic and including the main keyword |
| H2 / H3 headings | Logical sections; use questions people ask |
| URL slug | Short, lowercase, hyphens, keyword included: /seo-cape-town |
| Content | Answers the search fully, shows real experience, easy to scan |
| Images | Descriptive file names, alt text, compressed, modern formats (WebP) |
| Internal links | Link to and from related pages with descriptive anchor text |
| Structured data | Schema markup for organisation, local business, FAQs, products, articles |
Title tags
The title tag is the clickable blue headline in Google results and one of the strongest on-page signals. Write a unique one for every page, lead with the main keyword and add something that makes people click, such as a location, a year or a benefit. Google sometimes rewrites titles that are too long, stuffed or don't match the page.
Example: SEO Company Cape Town | Local & Technical SEO | HeftySEO
Meta descriptions
The meta description is the short summary under the title in Google. It doesn't directly affect rankings, but a good one increases click-through rate. Aim for about 150 to 160 characters on desktop (mobile shows less), include the keyword (Google bolds matching words) and end with a reason to click.
Preview yours with our free SERP snippet preview tool.
Headings: H1, H2 and H3
Headings structure your page for readers and search engines. Use one H1 for the page topic, H2s for main sections and H3s for sub-points. Question-style H2s ("How much does SEO cost?") help you appear in "People also ask" and AI answers.
Images and alt text
Alt text describes an image for screen readers and search engines. Write it for people: "SEO audit report showing Core Web Vitals scores" beats "seo seo audit seo". Compress images and set width and height to avoid layout shifts.
Internal links, canonicals and duplicate content
Internal links help Google find pages and understand which are most important. Link from high-traffic pages to the pages you want to rank.
A canonical tag tells Google which URL is the main version when similar pages exist. Duplicate content (the same text on several URLs) splits ranking signals, so merge, rewrite or canonicalise it. Use 301 redirects when you move or delete pages.
Questions answered
What is on-page SEO?
On-page SEO is optimising the content and HTML of each page, including titles, meta descriptions, headings, URLs, images, internal links and structured data, so search engines understand and rank it.
What is the difference between on-page and off-page SEO?
On-page SEO happens on your website (content, titles, structure). Off-page SEO happens elsewhere (backlinks, reviews, brand mentions).
How long should a meta description be for SEO?
About 150 to 160 characters. Google cuts longer descriptions by pixel width, and mobile shows slightly less.
How long should an SEO title be?
About 50 to 60 characters, or roughly 600 pixels wide. Longer titles get cut off with "...".
What is a meta description in SEO?
A meta description is an HTML tag summarising the page. Google often shows it under the title in search results.
Do meta descriptions affect SEO?
Not as a ranking factor, but they affect how many people click your result, which matters for traffic.
What are meta tags in SEO?
Meta tags are HTML tags in the page head that give information to search engines, such as the meta description, robots and viewport tags. The title tag is usually counted with them.
What is an H1 tag in SEO?
The H1 is the main heading of a page. Use one H1 that clearly states the topic and includes the main keyword.
Can I have more than one H1?
HTML allows it and Google copes with it, but one clear H1 is simplest for users and SEO.
What is alt text in SEO?
Alt text is a short description of an image in the HTML. It helps visually impaired users and helps Google understand and rank images.
What is a slug in SEO?
The slug is the part of the URL after the domain that identifies the page, such as "on-page-seo" in /learn/on-page-seo. Keep it short, readable and keyword-focused.
What is a canonical tag?
A canonical tag tells search engines which URL is the preferred version of a page when duplicates or near-duplicates exist.
What are internal links in SEO?
Internal links point from one page on your site to another. They help Google discover pages and pass authority to important ones.
What is schema markup?
Schema markup is structured data code that describes your content (business, product, FAQ, article) so Google can show rich results. Create it with our schema markup generator.
What are doorway pages in SEO?
Doorway pages are many near-identical pages created only to rank for slightly different searches (for example, one page per suburb with the same text). Google treats them as spam.
What is a 301 redirect?
A 301 redirect permanently sends visitors and search engines from an old URL to a new one, passing most ranking signals across.