I am also interested in this.. Do other people use the strategy Hakuna Matata uses? Or is it better to go over all the information yourself first, then meet in a group? etc.
I think group activities are something you have to be very cautious of. That's just my opinion. I see plenty of students who "study" in groups, although I wouldn't bet money on how much studying actually gets done. There are some successful group-oriented teams at my school, but I'd say they are the exception and not the rule. If you can find disciplined people who are compatible with your personality AND learning style, sure, try it out.
For what it's worth, I find most group activities frustrating if you don't have a semblance of the material mastered. Also, people learn in incredibly variable ways. Some people approach and attack material in a different order or find certain concepts easy that you may find difficult. Then, when you get together, this can often lead to a false feeling of idiocy, i.e. you're sitting there going, "How does this person know all of this?" What you'll often find is that they've simply started on material that you haven't yourself mastered yet.
Best use of groups/friends: Compare methods. My friends and I do this on a virtual daily basis. "Hey, Bob, how are you going to approach learning this material?" Once and awhile you'll learn something neat or a new method. Incorporate it and move on. Trick? Don't have crappy friends, less they'll gun you down. Also, don't be a jerk. Be comfortable enough in your own methods to share them with your friends and classmates. Truly great students need not worry about the "competition" from their peers.
Things I see that I find incredibly inefficient:
1) Elaborate study methods. I see people who will create these crazy elaborate study guides, complete with pictures, color codes, etc. Some of it comes off as sort of ridiculous and I'm not sure it's incredibly helpful. Are there outliers? Probably. There are a lot of overachievers in medical school and don't be intimidated by study guides that look they were done by a professional. Do take advantage of shared resources and give appropriate praise to those crazy enough to write them.
2) Spending too much time studying. Yes, I said this. The art of medical school is realizing that it is a lot of work. You will study more than at any other time in your life, but living in the library isn't healthy. Appropriate brakes or, gasp, days off are needed. A lot of work does not equal no down time. It just equals lots of work. Burn out is dangerous and I've seen perfectly smart students learn this the hard way.
3) Memorization over conceptual learning. A lot of stuff in medical school is straight-up memorization. Fact. HOWEVER, not everything can be successfully learned by brute memorization. Some stuff requires understanding the physiologic underpinnings of a disease and, surprise, it gets easier to understand and recognize on a test.
3a) Corollary to above: some stuff requires brute memorization, period. Identify what that stuff is and get to stuffing (pun intended) it into your head.
4) Don't be afraid to crack a textbook, especially books like Robbins. Some students will do everything in their power to avoid reading a textbook, sometimes to the point of simply not understanding the material. While it is true that many textbooks are virtually useless, that is not true of them all. Find someone who reads as a key component of their method of study and ask them, "Hey, which books do you find useful?" Likewise, be willing to ditch a bad resource quickly, so as to not waste time.
Notes: experiment with different methods. Some students still use paper pretty effectively. Others use iPads with Notability or other apps. PC users tend to like OneNote. The vast majority (way over 50%) of my class takes notes straight into the PPT. Find what works, based on the grades you're achieving, and stick with it.