1 Choose a Profitable Niche

However, in addition to sheer volume, there is one more very important consideration ‐ what your site is about, or to put it more professionally, which niche your site is in. Different niches aren't equal ‐ there are more and less profitable ones. There are niches, such as health or finance, where high value clicks are common and niches, such as culture or history, where you can make almost nothing with Adsense.

This is why you need to choose a niche where clicks pay well. It is true that good niches are very, very competitive but even in the most competitive niche, there is always place for one more good site. After you choose the niche, you need to find the high volume keywords in it and optimize your site for them. To search for keywords with high search volume, use the AdWords tool.