Almost all web pages have headings and sub-headings.
All too often, web designers code these headings with font information: basically saying “make this text large, bold, centered, and blue”. That works well to have the heading stand out for human visitors. But it doesn’t tell the search engines that those words constitute a “heading”. And we want to tell them that.
If we’ve got our keywords in these headings, telling the search engines they’re headings causes those words and phrases to be treated as more important than the normal body text on the page.
Heading tags
Heading tags come in six varieties: H1, H2, H3, H4, H5, and H6.
H1 is typically the largest and most prominent, and the other tags are usually progressively less pronounced, visually. If you’ve written your content well, you will almost always find your keywords in headings. Make sure the search engines know that by including heading tags in the code around those headings.
For a sense of how to use headings and subheadings, let me refer you to my blog post entitled The 7 Steps to a Perfect Blog Post.