Visually, the sites are a bit challenged. :)
There is no set guide for site 'beautification' unfortunately. You can jump into
Graphic Design feet first, ask a lot of questions and get a lot of help. They are always willing to lend a pixel or two. ;)
Read up on the importance of color and the affect it has on the viewers (and the designer).
Have you submitted your sites to site review? Are you getting any useful feedback?