The biggest thing:
Beast is only 6 weeks of your life. Some people love it (not many) and most hate every minute. it is less than 1 percent of your military grade at west point, so don't be upset if it doesnt turn out the way you want.
^Yes. Do not screw over your squad mates trying to get a better grade. A) it probably wont work and B) beast is a good time to star forging friendships, don't worry too much about grades.