Adsense Earning

Make good and fresh content .

"bring huge traffic without any cost" = learn SEO

You must know which keyword to target before you do anything else, eg. build link. So I think the first thing you need to do is to learn keyword analysis.
Try google this: "How I Generated **2000++ Visitors / Day in 3 months". There is one article from WF forum which I think is pretty decent.