Plenty of advice here:
1. If you want to study ahead, pharmacology is the class that kills most. The others are anatomy and pathophysiology.
2. Get all your personal affairs in order before you start school.
3. Be prepared, it is harder than most people think it is. The first couple of tests and grades at the end of the first semester are tough. Most of the students will be used to making A's. Being close to failing/barely passing is hard on the ego and some falks get cranky/flip-out.
4. I never really had to study before going to PA school, that changed. If you have just coasted through school up to this point, than you may be in for a surprise.
5. Do you like to read? Good, you're going to be doing a lot of it. It is almost impossible to read everything they want you to, like 100+ pages a night with good retention. Learn how to skim and learn what is important.
What is important for your instructors and what is important for your boards is different. Who the hell knows what you instructors will want but, First Aid for the USMLE: Step II is one of the best books ever, IMO.
6. The information comes at you fast. The oft repeated quote is, "Like drinking from a fire hose". It is not far from the truth.
7. Find out who the RT's, MT's, Paramedics, PT's, etc are. These are your resource people, use them. EKG's a problem schmooze your paramedic. Having trouble with the clotting cascade then track down your MT. Clueless about PFT's then get a mini-course from your neighbor the RT, etc. Get my point?
8. I don't know how others handled it, but I just kinda went into crisis mode at some point. What I mean is that there is not time to peruse the information at your leisure. It's more like, "What's gonna smack me in the face next?" Oh, I've got an anatomy final in two days, I should probably start studying for that. Once that test is over, Oh look I have an OSCE in clinical diagnosis tomorrow. I guess I should study for that!
If you are reasonably intelligent, work hard and give a damn then you will make it. Good luck!
All of the above is anecdotal and is just my opinion. Everyones experience in PA school is different. Listen to all of the advice and really pay attention to the things that multiple people say.
-Mike