Get to know all the members of your section. Practice playing alongside each of them individually. Make a mental note of each player's strengths and weaknesses. For example, if one player has a habit of playing slightly off-rhythm, make a mental note to work on the player's sense of time.
Practice and memorize your section's part for each piece the group performs. Read each piece of sheet music thoroughly. Practice playing the piece repeatedly until you can play it without looking at the sheet music.
Ask the conductor what your section should work on. Take notes on this so that when you meet with your section you will be able to work in harmony with the conductor's vision.
Assign parts to individual musicians in accordance with the conductor's plans. If the conductor tells who will play each part, simply delegate the tasks. If you are told to choose each player's part, assign the difficult parts to the more experienced and skilled players and the simpler parts to the newer and less skilled players.
Take the members of your section aside once a week and run through a the performance piece with them. Focus on the parts of the piece that the conductor wants you to focus on. Offer feedback to the section and to individual members at the end of these practice sessions. If the group is not in sync on rhythm, make sure the group knows. If one member is frequently out of step with the group, tell that member to slow down or speed up.
Inform the conductor about the group's progress. Tell the conductor how the section did in the most recent section meeting, Report strengths and weaknesses. If any individual members are having trouble, let the conductor know. Make a note to the conductor if the group is having trouble memorizing the piece, playing in time or playing in key.