From the start I've only used SEO basics.Nothing really special. But the good thing about it is all sites that I'm handling are ranking now on SERP and has good PR as well.
if you lost rankings, use a program like webceo or bp9 to analyize the new top 10 results and compare them to your site. Then make the needed changes, and viola! new top rankings. (sometimes) That's the best you can do. -RonMo