John has excellent suggestions! Do all that.

What I would add is this:

Beyond the preliminary daily drill stuff to get the horns warm, pitch established, etc., break the other drill exercise stuff up. Do your chorale then go to a chorale section of the rep. Go back and forth so that they see the relationship. Do an articulation exercise then an articulated passage in the rep. Don't waste time working a technique that you are not covering in the rep that day. Top band kids see the long game. 2nd and especially 3rd band kids do not.

Aim to fix one thing per rehearsal that you know will stick. Just one. Of course work more than that, but do not count on more than one or two things sticking. Work that one or two things until you know they are good - the rest is gravy for that day. By the way, music selection is critical to be able to do this. For my 3rd band I usually would not pick something that they couldn't read pretty well. The faster they sound better, the happier they are and the harder they work.

In the years where I was in front of both my 1st and 3rd bands, and took this approach, I found that many days I actually enjoyed my 3rd band rehearsals more than my top band. I expected my top band to improve and retain a lot more day to day (as they should) and it would be much more frustrating when they did not.