First, write down everything. Having a written schedule (or an online one, if you prefer), keeps you from forgetting vital deadlines, rehearsals, or performances. It also helps you figure out when you have some down time, because you're going to need it. A few free hours can give you a break or time to catch up on much-needed practicing or studying. Take advantage of even small breaks--fifteen minutes might be enough time to look over those three octave runs the music minister added to "Silent Night" to spice it up this year.
Which brings me to another suggestion: Keep Practicing! I know you're busy with performances and there's an unbelievable amount of music you have to play, and certainly a professional like you can wing it for a Christmas concert, right? Wrong. Remember that music minister? He also added five key changes to "O Holy Night," including one that goes from E-flat minor to C-sharp major. Fun! But seriously, you don't want to be the person who ruins a five-year-old's Christmas when you miss the high G-flat in "Let it Go." Playing professional gigs means you make an effort to show up as prepared as possible. After all, you want these people to hire you again next year. Yes, you do, even though you despise the music minister's key changes and three-octave runs.
Next suggestion: buy some hand sanitizer and Vitamin C, then wash your hands like mad after your private student with the runny nose coughs on you. There's something diabolical about the fact that the busiest season of the year coincides with flu season, but if we can't play well when all we want is enough chicken soup to drown in and a nice long nap. Besides, the flu can tra around orchestras (especially college orchestras) faster than those rumors about the flutist and the 3rd trombone. I remember my college orchestra after H1N1 hit; we lost two thirds of the string section and half the winds. So take care of your health!
Last, while I know the dire poverty musicians face (especially when we're in graduate school) can make us desperate enough to take ALL THE GIGS, try to pace yourself. You control your schedule--it shouldn't control you. If it comes to it, try to negotiate a better schedule--maybe your teacher will let you have a different time for your jury, or the music minister will be okay if you're late to a rehearsal.
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