If you did not have Google Adsense account yet, create one using the following technique http://theeasyway.blogsome.com/2007/01/31/the-easy-way-to-earn-money-from-the-internet-with-google-adsense/
Earning money with Google Adsense is simple, but there is a few tricks that you have to learn.
You can use search engine optimization to make your website as a number one in search engine list. Or you can trade link with friends, active in forum - but don’t forget - to put your url as your signature. Or many others way to make your site popular.
So, you know how to making money on the internet where you can do it at your home. You can make extra money by using Google Adsene, but now IF you have more than one website or blog, how you know from which site that you extra money coming from?
The easy way is to using Google Adsense Channel. In Google Adsense Channes, there an option for Custom or based by URL. The easy way is based by URL. Create a few channels to each of your site, so if you have two websites, and in one website you have a forum.
MyPets.com
MyPets.com/forum
MyPets.blogsome.com
You can create three channels, and use it as report category. Then you will know, from wicth url that give you the extra money.
With that, you can decide - you can optimize the site that give you the most money, OR you can optimize the other sites. It’s your choice.