One of the hardest concepts to teach is white space in design. Perhaps it is because the terms used to describe white space sound negative. White space is nothing. It's the absence of text; the absence of images. White space is emptiness. It is negative space. But it's not wasted space.
White space provides visual breathing room for the eye. It breaks up text and graphics. Add white space to make a page less cramped, confusing, or overwhelming.
Is there such a thing as too much white space? Yes, there is. However, it's rarely the case in the work done by non-designers and those new to desktop publishing. Usually we try to cram too much onto the page, afraid that we'll leave out something important. But without adequate white space, the important information gets lost. If all the text and images you want in a document are truly important and there is nothing you can cut out, use a bigger piece of paper.
White space can also be used to set a mood, convey a specific image. If you want a design to say "wealth, upscale, prestgious, elegant, or formal" then use lots of white space. If you want a more down-to-earth, informal, ordinary folks appeal, bring it down a notch or two. If you want to look cheap, mass-produced, or amateurish then fill the page to overflowing.
There are instances when trimming white space to the bare bones can and does work. However, in most cases, more of nothing is better.
Achieve a balance of ink and white space using a mix of techniques described in How To Add White Space, as appropriate to your design.
The Bottom Line: There is no proper percentage of white space. If a page looks or feels crowded, it probably needs more white space. In general, more white space lends an upscale feel to a piece. More utilitarian documents use less white space.
"Right and wrong do not exist in graphic design. There is only effective and non-effective communication." - Peter Bilak - Illegibility