Proper Use of Headings
Headings should be used properly to assist screen readers as well as sighted users.
The header tags (<h1><h2> etc) should be used instead of style elements like font size and bolding. If you want to change the appearance of the headers, use CSS to modify while retaining the header elements themselves.
Headers must also be used logically with only one H1 per page and the rest of the headers ordered logically.