This is a simple mathematical equation that one plus one always makes more than one. This is the bigger fact which can boost your adsense earning in days. Okey now let me tell what is behind the scene.
Consider if you have one website and you are publishing ads from adsense on it. Lets consider once more that it is giving your $100 a month. You will be very happy on it, but what if you have another site which gives you another $100 a month or may be even more of it. congratsss , your total earning is doubled.
This is the fact, try to make more sites with informative topics and put your adds there. There is no limit on the number of sites on which you can place your adsense ads. More sites you have , more revenue you will get.
To put another site online, it does not cost a lot. There are many web hosting companies which gives you multiple website hosting options. So you can have more than one website on a single hosting package. Just need to have a domain which is a few dollars in cost. Hostgator is the best choice for this option.
Once your site is online, put its link to your 2nd site and exchange the link both of them. So you have put a traffic pipe to your new site through your old one.
Publish informative articles and some other things on new site and wait for the time when its web traffic increases. Once you have the traffic, you will get a revenue from adsense and this site will add a plus cost to your overall earnings.