Short well written material with good navigation will attract the biggest audience. Avoid things that blink or move unless they have a very good reason for being there. Use a font optimized for the web such as Arial, Verdana, or Georgia. Make sure to spell-check your work. If possible have someone unfamiliar with the site read the material for content, grammar, and spelling.
Most people find it very annoying Color Limit colors to two or three complimentary colors.
Use high contrast between text and background. For example, the best contrast is black text on a white background. Also, remember that while white or yellow text on a dark background does provide good contrast, it is hard to print. Dark Green Text Avoid busy backgrounds. Background images which confuse the eye and make text difficult to see will discourage viewers from reading your content.