H1 headings should be used as main heading for your page, followed by H2 sub headings, then the less important H3 headings, and so on.
There is a misconception on the use and importance of heading tags, many used heading tags to enlarge or embolden the font of their text. In truth we have other tags and elements to control the look, colour and general appearance of our text.
Heading tags are used by the search engines to index the structure and content of your web pages. These tags are also used as a way of navigating your pages by the visually impaired. When it comes to Search Engine Optimisation a lot of stalk is put into the use of your heading tags throughout your pages.
Google’s algorithm pays close attention to the flow of heading tags throughout your website. A good implementation and use of heading tags within your website will result in a higher page rank.