Maximize Your Profits

Make your site's content clear, informative, and put out quantity without sacrificing quality so that search engines will love you.
If possible, customize your ads' colors. Make the background and border blend in with your site. Make the text coordinate. Savvy computer users tend to gloss over ads, so making them blend with your site's content should increase your number of clicks.
Do not use banners. When was the last time you clicked on a banner? See, people ignore them.
With AdSense, people tend to make more money with the content ads than they do referrals. Be sure to only put referral ads that relate to the kind of viewers your site will attract.
Market your site to increase traffic. Put your web address in the signature of your email. Talk about your site on message boards. Write articles for article sharing sites like Go-See.
Find the right balance. You may have to experiment a bit, but be sure to place enough ads that you get the maximum clicks you can per page, but also don't place so many ads that it annoys your visitors or they won't come back.
One of the most important things you can do is update your site regularly. If your site stays the same day in and day out, you will lose loyal visitors.
If you use Adbrite, don't start out your ad space pricing too high. You can always start out low and slowly raise the pricing as your traffic increases.
Don't stick with just one advertising program. They are free to join, so try out a few in order to see which one pays the best for you.