Making online money through adsense does need a good rank. You have to keep up our premium posts(ones getting maximum visits) updated i.e. kep on doing SEO for them at some times so that they never get hit and keep getting you visitors.
You need to Get higher go for google authorship . Better you google authorship better you will be with those results in SERP.
Use scraping URLs for dofollow links to rank higher.
they does the JOB well trust me. 10 of such good backlinks in 2 days will be show a result on 3rd to 4th day in SERP and you will get to know yourself what i am talking about.
See this:
square root of a number without using sqrt()