A post over on ViolinExcerpts.com has 39 great tips for rehearsal etiquette for just about any ensemble. Although some of these are pretty obviously string- or woodwind-related, the vast majority are great for all musicians, if you want to be thought of as an asset rather than a hindrance in any large (or small) ensemble!
Some of the best ones:
Never sight read in rehearsal. Prepare your part in advance.
Never complain about your reeds, strings, bow hair etc. (mouthpiece, sticky valves, etc.)
Your pencil is your best friend…. Do not make the same mistake twice because you “forgot.”
Check out the entire list over at ViolinExcerpts.com