What onLoad wrote is helpful but in the end, you can't be 100% sure you will be accepted. But by doing that you definitely are close to those 100%
make sure your site is good and have content or offers a service! stay away from warez and from illegal sites...
If you haven't already applied, create a blog on blogger.com and apply with that. Usually it is almost guaranteed (not absolutely, mind you) that it will be accepted, and in a much shorter time. (ours took less than an hour.) Make it good quality, with several useful posts, and make it a blog that has content that would enhance an advertisers ads... like, don't just make it a personal blog about your family daily doings (some of these may be accepted, but it's a risk you don't need to take)... maybe make it related to your site? It doesn't have to be really commercialised, but not something they look at and say "I can't see how any relevant ads could be served here... or benefit the advertisers if they were!" It used to be that basically any blog got accepted, but I've heard a few people saying they got turned down recently. So, don't just make it crap, certainly not stolen content. After posting for a few days or so, apply for Adsense with this. Then, once you're accepted, you can also put Adsense on your other site without re-applying. But make sure this site is also quality and is within the Adsense TOS. Or you could end up being banned in time, or at least that site may be. Good luck. Let us know when you get the nod from "The Big G"!
1)Your website should have Quality and Unique content 2)It should be navigable, that is, no more discomforts for the visitors to browse around 3)Should not contain any obscene, vulgar or adult material