Probably the most important things are the basics. Show up on time, answer pages propmptly, care about your patients, be polite to all hospital personnel, and do what is expected. Different schools may have slightly different expectations as to exactly when student notes are to be on charts, what call is like, etc. Expectations also tend to vary with rotation. I'd recommend arriving at the hospital about 20-30 minutes earlier than you think you need to at first, as it can take a lot longer than you think to see even 2-3 patients when you are getting started. (I alloted myself 1/2 hour per patient at first) You need time to track down where labs and vital signs are recorded, and time to think about what you will write in your note. Make sure you write down all information about your patients on a paper you keep with you for your presentation. You'll need to know all vitals and labs and medications as well as the patient's subjective information and physical exam findings.
Be willing to do a bit extra to track down information pertinent to you patient. At most of the hospitals I rotate through, it is rather common for a lab test or xray of some kind to not be done, despite being ordered. I learned early on to try to expidite getting it done when I am seeing the patient early in the day. This can be done by very politely asking the nurse: for example I might say "Excuse me, I see this lab was ordered, but I can't find it anywere. Is there somewhere else it might be, and is there some way to check and make sure it was drawn?" DON'T demand "Why wasn't this lab done?" (I've seen students do that!!!). If you take a few minutes to do that with labs, you might have the results by the time you start rounds. For x-rays, it's nice to be able to say, for example "Mr X's CT was ordered yesterday at 2pm, but wasn't done, so I called CT and the scheduler told me that they would get his done first today". Then follow up on that - later in the day, check and be sure it was done. Another handy thing is to find out how to check the dictation system. That way you can call and listen to the results of imaging studies before the report is transcribed and put on the chart. Also, I like to go to radiology and look at films myself. I have found most radiologists to be very willing to do some teaching and point out the findings as well as answer questions.
Do your presentations in full format, (ie say everything, even exam findings that are normal) until you are told that you only need say the pertinent stuff.
Focus your reading on your patient's conditions at first. Then expand to cover other areas. Try to pick one main source for reading, and do some practice questions to prepare for the exam. If there is an oral exam involved, ask the residents if they can give you a few sample orals.
Otherwise, be a good team player. Share the workload with your fellow students, and share any procedures you will be allowed to do as well. (However, don't go overboard by keeping a written log of who did what and when...I've seen students do that, too) If you have a beef with a fellow student, take the issue up with him/her privately. There is something interesting and valuable in every rotation, find that aspect early on so that "acting interested" isn't an act. At the midpoint of your rotation, ask for an evaluation (even if it's not required). Try not to accept "you're doing fine". Ask further what you should improve. You can even ask what grade you would get if final evaluation was today.
And finally, never fudge when it comes to patient information. If you are asked something about your patient (example a lab value), and you don't know, say so. Then next time, include that info on your notes. It's OK to make educated guesses on generalzed pimping questions, but not on patient data.
Most important, have fun. This is a lot better than the first half of medical school.
