All this brilliant advice comes from the Passion4Jazz site
Tips for the Jazz Musician– A few things to remember at the gig.
-Everyone should play the same tune.
-Always wear dark glasses, the darker the better. You won’t be able to see a thing but people will think you’re deep and mysterious.
-Stop at every repeat sign, and discuss in detail whether to take the repeat or not. The audience will love this a lot!
-If you play a wrong note, give a nasty look to one of the other cats.
-When talking into the mic, start everything with “Hey man…”
-Keep your fingering chart handy. You can always catch up with the others.
-Carefully tune your instrument before playing. That way you can play out of tune all night with a clear conscience.
-When hitting a high note, always throw your head back and make a grizzly face expression.
-Take your time turning pages.
-The right note at the wrong time is a wrong note, except among the tone-deaf.
-If everyone gets lost except you, follow those who get lost.
-Strive to play the maximum NPS (note per second). That way you gain the admiration of the incompetent.
-Markings for slurs, dynamics and ornaments should not be observed. They are only there to embellish the printed score.
-If a passage is difficult, slow down. If it’s easy, speed it up. Everything will work itself out in the end.
-If you are completely lost, stop everyone and say, “I think we should tune”.
-Happy are those who have not perfect pitch, for the kingdom of music is theirs.
-If the ensemble has to stop because of you, explain in detail why you got lost. Everyone will be very interested
-A wrong note played timidly is a wrong note. A wrong note played with authority is an interpretation
-A true interpretation is realized when there remains not one note of the original.
-When everyone else has finished playing, you should not play any notes you have left.