Keep trying to get more traffic to your site. Work on SEO. Also, make sure that the ads are placed well, in prominent positions where people will see them.
This are some tips from me: 1. find an aged domain with PR 2 or 3, better if you using EMD domain (if you can't fid the aged domain, you can get new domain also) 2. Research keywords with low competition using allintitle tags at google, lower than 3000 competition, with EXACT search volume minimum 2000, preferably more than 5000 per month (local search) and CPC minimum $1. 3. Create unique content for the keywords 4. Do on page SEO for the articles using SEO Scorer by George katsoudas, or SEO pressor by Daniel Tan, this tools can give you direction how to do onpage SEO. 5. Also using Wordpress SEO by Yoast (better than all in one seo) because It works perfectly with seo scorer or seo pressor. 6. Post the content 2 - 4 articles a day, if you do't have time on daily basis, you can schedule it. 7. Don't forget put title and description on root for selected keywords (3-5 kwd max), For description you can make a calling senteces so the visitor want to click to visit your site. 8. Then do some seo for root and each articles, you can use web 2.0, social bookmark, twitter, facebook, google+ and buy link consistenly (depends on your budget, you can find in this forum for that kind of services) 9. Do it consistenly, work hard, and patien...don't expect quick money... I hope you can gain great success with adsense...