If you don't have a decent amount of traffic already visiting your blog, you will most likely get denied by Google Adsense. Your traffic should be natural and legit. Don't buy traffic from anywhere because it's useless and can get your denied or your Google adsense account revoked!
So if you don't have much traffic now, you might want to hold off on applying to Google. Try adbrite.com or amazon.com so your traffic gets use to ads being on your site.