Ok, I'm going to jump around a little bit here and let you in on one thing I learned the hard way.
Use the Channels feature!
I can't stress that one enough. I had many many pages set up when I realized that I would never know what traffic was going to what page. It's easy to set up the channels as you're building the ads, use them!
As for ad placement and colouring, google has some excellent help on their site. I also got a hold of a free google adsense book which is quite good. Ignore 95% of the get rich quick schemes floating around on the net. They're only making the people writing the schemes rich!
When I find the link for that book, I'll post it.
BTW: For people who live in a cave, or are real newbies, google gives you code snippets to put on your web page. These snippets turn into the google ads that you see all over the internet. The ads are generally targeted to the content of the page they are on. For instance, if your page is a recipe for muffins, there will likely be ads for muffin recipes, weight watchers and maybe even muffin mix.