I can't sync my apps from my itunes to my new iphone 4?

I bought a new iphone 4 and am trying to sync my apps from my itunes to it. But it is not working and I have no idea what to do. I've been very frustrated with the iphone 4 so far.

Do make sure that you did Authorize the computer to sync the iPhone with it.
Also make sure that the apps are compatible with the iPhone