Aside from what Bazza gave you ( http://www.webdesignfromscratch.com/...tyle-guide.cfm )

You can visit this site: http://www.go2web20.net/ for guide on the latest trend on web design.

You should also learn how to use CSS based layout as this is now the web standard. Table layout is not web standard. Your site may appear like the "Web 2.0" trend, but if you're still using tables, then you're on the Web 1.0 era. Though i'm not fond of this Web 2.0 thing.