Before you even begin your site, make sure you've come up with a topic that you feel you know plenty about. That way it will be easiest to write a lot of content.
The more content you have, the better chance you have getting accepted into the program. Also, the more content and traffic, the greater the earning potential.
If you want to make a lot of money, prepare to write a lot of content and learn how to market your site. Don't expect to throw up a 10 page site and make $1,000 per month. That's unrealistic.
Now let's talk about building your website.
