Establish Starting Routines
When I first started team-teaching with Wes Barry I noticed that when he started the band everyone played. When I started the band, some played but some did not. I asked him what I was doing wrong. He said I needed to look around and make sure they were all ready to play before I started conducting. That was an easy fix. It only took a second or two and it worked well.
It didn't work quite so well at the junior high. What took only a second or two at the high school seemed to take forever at the junior high. To solve the problem, one of the directors I observed used assigned positions for the instruments.
Rest position (when the conductor is not on the podium) - The smaller instruments are held diagonally across the students' laps with the mouthpieces over their left knees. The trombones rest the instruments against their left shoulders. The horns rest the instruments against their bodies. The percussionists stand a step behind the instruments.
Ready position (when the conductor stands on the podium) - The smaller instruments are raised to an upright position with the bells on the students' right thighs. The trombones are pushed out to an upright position with the bells on the students' left thighs. The horns are pushed to an upright position on the students' laps. The percussionists step up to the instruments.
Playing position (when the conductor raises his baton) - The blowers bring their instruments into playing position. The pounders bring their sticks and mallets into playing position.
Using the instrument positions helped a great deal. We had fun practicing moving the instruments from one position to another.