Rehearsing intelligently is the key to a successful performance, and a happy band.
Planning a rehearsal is possibly the most important task any band or band leader can do. It shows respect to the people you called -- by showing you are considerate of their time and that you feel they of a high enough caliber to do work ahead of time to make sure their contribution to the rehearsal is significant.
Four major things need to be done to plan a rehearsal, and thus rehearse intelligently. Prepare, determine the purpose of the rehearsal, determine the structure of the rehearsal, and most importantly stick to the purpose and structure of the rehearsal.
Further entries will expand of these concepts.
Keep in mind, the concepts I will present work well in the meeting room and the classroom as well as the rehearsal room.
Also, these concepts are meant for professionally minded groups, not for "cult of personality" bands, or groups getting together for the pure fun of it. The previous will find the general order and respect for band members counter to thier purpose of having a band and the latter may find it can be too focused (although this group may find if they want to up their game, or move to the next level they can apply some or all of these techniques)
Also note when I say "professionally minded", it doesn't matter if you make dollar one with the group or ever intend to,just that you have the desire to present a high caliber and well crafted performance.