Good Question. I've found a video (yes another one by Lisa), about how to tackle issues you may be experiencing with adsense so you an receive larger checks:
I saw this before and agreed with her back then and still agree today. Like Fergal said, the niche you decide to embark on should be a priority topic in your life, whether it be work or a hobby; it has to interest you.
I agree. You have to choose a niche that you have an interest and are passionate about or else your going to get board and you won't like updating your site, forum, blog, whatever, and you won't have as much luck earning with google adsense.
