I think the study skills that will be successful depend on a number of things. Some professors give fabulous notes that give you as much info as you could want and/or need. Others will leave much to the imagination, and you may need a text to figure things out and teach yourself. It is also important to know if you are more efficient at self-studying, group studying, or a combination. That can depend on the subject you are going over. I think the main thing is to find out what works and then stay consistent and diligent with it. This is especially true in the case of time management, because as the saying goes "med school is like trying to drink out of a fire hydrant...." It isn't that the difficulty of the material in and of itself is exceptionally more difficult than the stuff you probably took to get to this point, it is just the sheer volume that you are required to process at a given time.
I never studied in undergrad, except the night before the test. I study everyday now. So for me, just the time factor alone took some getting used to. But you'll figure it out. Congratulations and good luck.