When you have a large amount of text in a post, it’s important to break it up with sub-headings, and you’ll find those in the format or paragraph drop down menu on your Visual text editor  (technically, it’s the format menu, but most of the time you see it displaying the paragraph setting because that’s the default in the text editor).

IMPORTANT:  Do not use Heading 1 or Heading 2

The headings in the text editor’s drop down menu use a set of HTML tags, which not only have specific styling in your theme’s style sheet, but more importantly have special meaning to search engines.  Heading 1 uses a tag that essentially says “I’m the title of this HTML page,” while Heading 2 uses a tag which essentially says “I’m the title of this post.”

If you use either heading for the subheading of a post, you’ll confuse the search engines (and visually you’ll confuse your readers too).

For subheadings, stick to Heading 3 or lower.