Create a Clear Visual Hierarchy

Organize and prioritize the contents of a page by using size, prominence and content relationships.

Let's look at these relationships more closely:

Size
The more important a headline is, the larger its font size should be. Big bold headlines help to grab the user's attention as they scan the Web page.
Prominence
The more important the headline or content, the higher up the page it should be placed. The most important or popular content should always be positioned prominently near the top of the page, so users can view it without having to scroll too far.
Content Relationships
Group similar content types by displaying the content in a similar visual style, or in a clearly defined area.