Search the forum (hint, try both AIB and Admiralty ...) and pay attention to anything written by Cobaltfrog. Try PMing him.
I had the great pleasure of passing the AIB for Pilot 29 years ago next week. I can't imagine the objective or the methods have changed that much; when in the group session don't try to get a group decision until everyone has had a chance to put their point across, and if necc., make sure that they guys who don't speak up are given the chance. There will be one guy who tries too hard. Watch him dig himself in for a short while before stepping up.
Take the practical phase at a steady pace, and remember to describe your objective, detail the plan, take questions/criticism, and delegate.
Don't be afraid to speak for/write what you believe in. The essay phase asked us to write for or against conscription. I argued strongly against it, but I expect a few thought they'd better look keen and agree with it.
If they ask you a closed question (ie one to which the answer is yes/no) then expand your answer. If they ask you an open question then get your answer in, and then stop, don't ramble/waffle on. If you've got some info about you that want to get in, do so, when appropriate, without waiting to be asked if you've ever done xxxx.
Try not to try too hard - they want to pass you.