If your AdSense is not working there is a good chance that you have tried to sign up to it too soon. Your blog needs to be active for approximately six months before you can qualify.
They do this to help prevent spam accounts.
After six months you should be able to sign in and start running Ads from your blog.
Google AdSense is an advertising placement service by Google.
In the meantime, Paul recommends you sign up to Amazon’s Associate program.
Please note that Paul does not focus on this AdSense strategy in his program, as making money from AdSense requires you to drive a lot of traffic to your blog, which will very likely not be the case when you are just starting out.