Clean is better. Eye-tracking studies say so. Your web copy should be concise and to the point. White space is good. If your user is comfortable and unhindered by “clutter” they will be more likely to get the summary of your site quickly and easily.

Think bullets and subtitles. Your content should be easily scannable. People like lists.

Fonts. Stay away from fonts like Comic Sands and Brush Script, at first glance your site will feel unprofessional. Don't use these or other fancy fonts that may not be available on most computers. If the font you use is not available on a visitors computer, the web site will use a default font which is much worse. San serif fonts are easier and faster to read on computer screens. Try to stick to fonts like Arial and Veranda. 

Font size. Bigger is not necessarily better. Give your site a sleek, clean appearance, by using appropriate font sizes. But also keep in mind the diversity of platforms used to access sites. Anywhere from portable devices with tiny screens to projection devices hooked to computers. Legibility is a must!