I found it was easier to get an adsense account after I set up a website. Make a website on blogger for free about something you know a bit about and put up a few quality pages. Then apply to adsense. It took about 2 weeks to hear back from them and I was in. I made a site about Elizabeth Taylor.
In the meantime, or if you continue to be rejected, I'd suggest trying Squidoo or Wizzley as it's not necessary to have an individual adsense account to earn there. Squidoo uses their own adsense/amazon/ebay codes etc and shares the revenue with you. On Wizzley you can opt to monetize using Chitika - great for those without an adsense account etc.