In the first 4 posts in this series on making money with AdSense, I covered the creation of an ad-enabled website. Now that your site has been running for a while, you'll want to monitor the AdSense reports and watch for traffic. As I've mentioned previously, search engine traffic will take a while to build. But rest assured, if you continue to add content and follow the SEO best practices, you will get traffic. Once you do, you should start paying attention to how your ads perform.
Google, be default, does not provide you page level data. Instead, you need to manually create channels and associate these channels with different ad blocks in different parts of your site. Depending on the structure of your site, this can be as simple as creating a channel for left side ads and a channel for right side ads. More complicated sites may benefit from more channels to get more granular data. The objective with channels is to do tests by moving ads around your pages to see where the best spot is. You can also track the performance of wide ads vs. narrow ads. Using the data you get, you can then decide where your ads should be.
From what I've read, ads that blend in to the site i.e. use the same color palette work the best. And ads along the left perform better than ads along the right. I came to these conclusions after a lot of testing. And yes, while you're testing you may reduce your earnings since you will undoubtedly put an ad in a bad spot. But this short term loss is worth the long term gain.
And that's all there is to it. Repeat parts 4 and 5 for as long as you can and you'll end up with decent ad revenue. Repeat all of these steps multiple times i.e. create different websites and you may even be able to quit your 9-to-5 job although I don't recommend it. We may be in an AdSense bubble and you want to have a back up plan in case it bursts.