Hi Julia
Have you read up on SEO (search engine optimization)? Do you know what keywords you are trying to get found for and are you building your pages to target these keywords specifically? I get a lot of my traffic from the search engines which of course turns into Adsense revenue. Just wondering if you've made any progress with SEO because that would be a start.
Here is a great introductory article from one of the most popular SEO sites.
http://searchenginewatch.com/showPag...age=webmasters