One of the most important things to remember with Adsense is, Less is More.
Some Bloggers think if the ad is their as soon as the page loads, im going to get a click, well it dosent work like that. People have visited your page because they wanted to, not just to come, click the ad and leave. A lot of Adsense publishers actually hide their ad away in a corner, it works better for them.
Everyone is different and it will take time for you to find which ad size, colour and placement is best for you, try different ads every few weeks and see how your earnings differ.
Google also has YouTube video clips as well as the normal Text and Image units, why not try these out too, you can find these in your Adsense account under Set-up.
Adsense - Less is More
