Good on-page SEO structure helps both people and search engines understand a page quickly, and most of it comes down to headings, images and links.
Search engines read a page's structure to understand what it's about. People use the same structure to skim and find what they need. Getting it right helps both. This checklist covers the structural items that Smart SEO Scanner checks in its reports: headings, images and links.
Images are often the heaviest part of a page. The HTTP Archive Web Almanac 2024 reports that the median mobile homepage loads about 900 KB of images, and 1,054 KB on desktop. The same report notes that a Largest Contentful Paint of 2.5 seconds or less is considered good, while anything over 4 seconds is poor. Compressing and correctly sizing images is one of the easiest structural fixes.
Headings (<h1> to <h6>) break your content into sections and show how ideas relate to each other.
Each page should have one H1 that states the main topic. It usually matches or closely relates to the title tag. If a page has no H1, search engines and screen reader users lose the clearest signal of what the page is about. If it has several, the main topic becomes less clear.
A common problem: some website themes wrap the logo or site name in an H1 on every page, so the actual page title ends up as an H2. The scan will show which headings it found, which makes this easy to spot.
Use H2s for main sections and H3s for subsections within them. Don't pick heading levels just for their font size. If you want bigger or smaller text, change the styling instead. A good test: if you read only the headings, would they form a sensible outline of the page?
"Overview" and "More info" don't tell anyone much. "How long shipping takes" and "What's included in the kit" do. Descriptive headings help skimmers and give search engines extra context.
Images make pages more useful and more engaging, but they also cause some of the most common SEO and speed problems.
Alt text is a short description of an image, added with the alt attribute. Screen readers read it aloud for visually impaired visitors, and search engines use it to understand the image.
alt="") so screen readers skip them.The scanner lists images missing alt text so you can work through them.
Large images are the most frequent cause of slow pages. A photo straight from a phone camera can be several megabytes, while a properly resized and compressed version might be a small fraction of that and look the same on screen.
A descriptive file name like waxed-canvas-tote-green.jpg gives a little more context than DSC0042.jpg. It's a small thing, but it's free.
Internal links connect pages on your own site. They help visitors find related information, and they help search engines discover your pages and understand which ones matter most.
Linking out to helpful, trustworthy sources is fine and often good for readers. Just make sure the links are relevant and the sources are reputable.
Links that lead to error pages frustrate visitors and waste search engine crawling. They're common after pages are moved or deleted. The scanner reports broken links found on the scanned page. When you find one:
Reports also show the ratio of visible text to code on the page. A very low ratio can mean the page has little real content, or that it carries a lot of unnecessary code. It isn't a ranking factor on its own, but it's a useful nudge to check whether a thin page could be more helpful.
Most visitors are on phones. Make sure:
Run a free scan on your most important page and work through this list. When you're done, see how you compare with a competitor using the site comparison tool. Questions? Contact us.
HTML allows it, but one clear H1 is the simplest structure for readers and is easy to audit.
Describe what the image shows and why it's there. Decorative images can use empty alt text.
There's no fixed number. Link where it genuinely helps the reader find related information.
Clear headings help search engines and readers understand the page's structure and topics.
Run a page through Smart SEO Scanner to see headings, image alt attributes and links in one report.
Smart SEO Scanner is a Justin Zwick project. See all projects. Last updated .