You should break up your content into minor sections & paragraphs to make it easier for people to read. These sections can be given heading, which is where H1, H2, H3, H4, etc. tags are used. Make sure you write keyword rich headings in the order of importance in H1, H2 and H3 title tags. They are used by many crawlers to differentiate important content.
<h1> On-Page Search Engine Optimization </h1>
You should include Alt Text and Descriptions for your images, making them even more useful with SEO. Image increase visually and you can use images to help improve your site SEO.
<img src=”your_image.jpg” alt=”Image Descriptions” />