Use of Heading Tags
Many people are aware of the importance of header tags. However, there are ways to use them that will increase their impact. First, the larger headers–h1 and h2–have a greater impact on crawlers. Second, you should use tags in order–h1, then h2, then h3 and so on. Skipping from h2 to h4 may look better in some circumstances but it is not as good for SEO.
While header tags are important, you should avoid overuse them. Don’t keyword stuff in tags, and avoid using a h1 tag more than once on a single page. Most important, do not use them as hidden text. This will result in a penalty from search engines.