Try to play every day, even for just a few minutes.
Do buzzing exercises as a part of your warmup, make sure to hold the mouthpiece by the end and to focus on your air and the strength of the buzz, not on making big changes in your embouchure.
Start thinking more about your breathing. Take the air in low, over a couple of seconds.
Continue work on the C major triad, C E G C.
Work on moving between A (the fingering is 1 and 2) and C.
Keep doing work on just moving through your range and feeling where all the notes fit in (if that makes sense, my vague instructions may not be as clear in writing )
Be aware of your posture; sit as if there is a string holding your head up to a neutral position (like a marionette). Keep your feet flat on the floor, and sit at the edge of your chair.
Try to find your band music!