So you should start from here.

Supposed you have created a gmail account, a blog and an adsense account.
Then what should you do??
The main thing is there that you should increase your site traffic that means visitors.
Without visitors you will not get money.
So How will you get visitors ??
This is the main secrete of Internet that how people are increasing traffic/visitors.
To increase traffic you can use advertising company like adbride,bidvertiser etc. But you should pay to advertise your site on that company.

Later I will show you more secrete on Visitors