Any area on the page that is not occupied by text or graphics is the "white space." Think of coming across a page in a book or a Web site page: it becomes intimidating to be faced with long, flowing, and uncut pieces of text. White space is needed to visually ease the reader from becoming overwhelmed in receiving the information.

White space can be used to make a better presentation of the information. The presentation really does make a difference in how the content is perceived in a document. The white space makes the document more inviting to the reader. Use white space in the following ways:

To create space before and after headings
To widen the margins on all four sides
To create space between columns of words or numbers
To create space between paragraphs
To create space between bulleted items
To define sections of the document
To frame the content

After all, which document is formatted to enable audiences to read and comprehend its contents? This one? Or, this one? (Hint, you should be producing documents that look more like the latter rather than the former example.)

(From Tips for Technical Writers)