As in, pop the condensers out of their brackets and clean out all the crap from between them and the rads. You'll be shocked at the amount of debris in there. There's a good youtube vid out there if you need a bit of help.
Since you're asking about other parts, I'd hold off on the job until you get 6 or so of the plastic rivets for the bumper cover. You won't need them all, but they're cheap and you'll need them eventually.