First, you need to know that John Wooden was the most successful basketball coach ever . . . but you still might wonder, what does that have to do with me? As head coach at UCLA, he won 10 NCAA championships in a period of 12 years, including a streak of 7 in a row. This was not only an unprecedented record, but he won with different types of players and teams, from his early championships with small, fast teams, to the teams dominated by Lew Alcindor/Kareem Abdul-Jabbar. And his success was not just in winning games, but in building the character of his players. He considered himself a teacher above all, it is from his teaching and leadership skills that we can learn, despite the fact that we're in very different fields.
I'll start with one idea that I found very useful (and mentioned in a blog post last year): that of the difference between scrimmage and drills.
One of the noticeable things about the way Wooden worked his UCLA teams was to spend much more time in drill (focused on specific skills) than scrimmaging (playing a mock game). The advantage was that in drill, he could focus his players' work on skills and techniques that needed work (passing, shooting, defense, etc.), whereas in a scrimmage, only one player had the ball at any one time and less work for each player.
I introduced this idea to my choir last year (and this one, too), equating scrimmage with a run through of a piece or section of a piece--valuable for both me and them to see where they were, what worked well and what didn't (and, of course, to get the experience of singing through the entire piece, which is what they'll do in the concert). However, I explained that we would accomplish most with drill, where we worked the difficult sections of a given piece of music, or focused on pitch, vowel, rhythm, vocal technique, or whatever else needed special attention. Sometimes, I simply said, "scrimmage," so they'd know they were doing a run-through, and to work towards what the performance would be (and to note what was and wasn't ready yet).
In drill on the other hand, they knew they were going to do multiple repetitions of something, perhaps only a few notes, but with great focus on whatever elements were brought to their attention.
They got the concept very quickly, which has meant a much greater rehearsal density for my choir. There are other elements in building this, but I hope you get the idea as well.