Yeah I use Analitycs for one of my Adsense sites. It gives you info which pages bring you the most money. Promote those pages and you will get more $$$
Hmmm, what about using analytics to improve the ones that AREN'T performing well...you know, bring them up to speed.
You cant, I dont think Analytics tracks channels. <?That would be cool if it did?> It will tell you which page the ad was clicked on.
Use one ad block. Don't use more than 2. The best ads appear then and you get the best eCPM. http://www.grokdotcom.com/2009/02/16/the-missing-google-analytics-manual/