Headings or header tags play a vital role in telling Google where the important stuff is within you page. It allows it to gather and organize your content too. Whenever possible use heading tags to show importance & hierarchy in your web document.
For example use H1 as the main heading at the top of the page to introduce the site’s subject matter. Then use H2 for subheadings on the page. You can use more than one if nessesary. Then H3 can be for smaller sub-subheadings or titles nested within H2 parent headings.
Avoid jumping from a H2 to a H4 or jumping backwards from a H3 to a H1 for example. Make sure to insert relevant keywords within the headings as well.