You've probably placed this in the wrong forum. The simplest way to increase the number of visitors your site therefore increasing the amount of money you make through Adsense would be to post high quality unique content and slowly build a number of relevant backlinks to your sites. The quality of the content is really core and obviously being in noncompetitive niche also helps.
Posting quality content on your blog is key. But also working towards getting your blog to the top of google search (or as close as possible) for your niche will also help increase your earning because it will drive more traffic back to your site. As said above, setting up backlinks is also helpful. Targeting keywords that are relevant to your site as well, which have a low competition and high search volume can also be helpful
Input more quality and informative content, it helps to maintain the current visitor and get more new visitor