Had a study group of 8 through indoc, it was awful. Systems slimmed it down to 4 (1 more came on the 2nd week) and I felt 10x better in class and after class. Friday night after class put your stuff down, go out with the guys/gals. Have fun. Sleep in, relax, Saturday night and Sunday get back to studying. Worked pretty well for my group. Make sure everyone in your group is on the same page before moving on. I enjoyed electrical systems and felt very good about it, but my class roommate didn't. Visa versa I didn't feel great about hydraulics and flight controls. We all spent our time to bring everyone in our group up to the same level, never let a man fall behind.
Have fun!