There is no one specific thing I need work on, I basically have to work all of the fundamentals to overall improve. I do not plan to work on fundamentals/technicals exclusively; I will also practice my parts for community band. I do want to say that the primary weakness right now is... weakness! I need more time on the horn to build more endurance. I am not generally able to finish a two-hour rehearsal playing the same as I did at the beginning.
From one community band player to another, I can tell you that the long tone and lip bend routine I've been doing for the past year has done amazing things for my range and endurance. But like others have said, there is no substitute for unforced lip time. Play easy, think tone and resonance, put in the time, and above all have fun and make music.........