I came across this article on Digg.com. It contains pretty concise tips that I can follow and make sure I'm doing. Since I'm not a designer and don't necessarily have the best ability to choose matching colors and appropriate fonts etc, I find articles like these helpful to bookmark for reference when tuning my sites.
From the article:
Web design can be deceptively difficult. Getting a design that is both usable and pleasing, delivers information and builds brand, is technically sound and visually coherent... So here are my 9 principles for good web design with examples and further reading!