Rehearsal Habits. Set agreements as to lengths of rehearsals, degree of punctuality (if everybody is an hour late all the time, it’s not a problem — if three people are on time to the minute, and a forth is always 20 minutes late, things will get ugly). Also, there should be consensus on the levels of preparedness. Is it OK to come to rehearsal without having looked at the parts? Must you have your part memorized and the entire score as well? Certainly, different levels of preparation are required at different times, but having some agreement/understaning before hand will do much for the general attitudes during rehearsal.
Geographic Location of members. If ensemble members do not live in the same area, it is important to come to an understanding of how and where rehearsal will be held. Will travel expenses be shared? Will the venue rotate?
Human (inhuman?) Interaction. It is good to talk about the ways to treat each other in rehearsal. We all come from different backgrounds and what is efficient communication to one may be rudeness to another. Learning each member’s personal style can save lots of aggravation and stress. For example, one ensemble member comes from a family that speaks quietly, is reserved, and does not interrupt. Another player’s family is boisterous, animated, and unrestrained. The potential for both parties to feel frustrated by this mismatch is great. Understanding this can help avoid problems. By the way, the things that may be most frustrating about a colleague are often a balancing strength. Remember, a great ensemble must have enough contrasting flavors to be interesting. Of course, too much ‘interesting’ is sometimes fatal.