Some quick tips to help improve your ensemble playing:
1. Tune without vibrato
2. In music, especially classical, it is very important to have more “bottom” (bass instruments) to the sound, so make sure that the lower instruments are audible
3. Listen to the other musicians in the ensemble and try to match dynamics, intonation, vibrato, phrasing, articulation, time and balance
4. Listen to your principle players and play slightly softer than the person a chair over you
5. If there are discrepancies interpreting the music, ask the conductor how to interpret that part of the music and play it the way they tell you. A good conductor will have done research on the piece you are performing and will know the proper way to interpret the music.
6. When you are in a group with strings – you have to think about what a string player can and cannot do, then play with that in mind
7. Get out of the way of the melody – that should be the loudest and most clear part of music
8. Play light articulations to blend with the rest of the players.
9. Find a recording of the piece you are playing and listen to it.
10. And last, but most importantly – ensemble playing is about listening – so use your ears.