I agree that looking through the process archive is a great place to start to learn how the process goes.
It's all good and well saying lurk for a couple of CAPs but when a whole project lasts at least couple of months and the downtime between projects is almost as equally long, it can be frustrating for newcomers to sit back and wait nearly half a year, if not longer, before they feel like their participation would be accepted.
So I disagree with lurking as long as three conditions are fulfilled:
-The first is to definitely read the process archives, get a feel for what happens in each stage, and how to discuss each part (that means learn the CAP lingo and format of discussion).
-Learn the OU metagame if you already haven't, after all CAPs are created with that in mind. Before you write about an existing pokemon, ask yourself if its currently relevent in OU and if it is does it use the set that you're going to bring up.
-Finally, and most importantly, listen to the advice that experienced CAP contributors give you, if you don't understand where you think you've gone wrong, just ask. It's alright to make mistakes as long as you learn from them.
Anyone with a modicum of intelligence should be able to do the above successfully and then go on to enjoy their inaugural CAP.