If you gather students who can read music and play instruments normally, you can make a "good band (normal band)". If you teach with the goal of nurturing such students, you will definitely make a "good band".
  However, teachers who are not used to it try to skip this "very obvious step" and fail, just because they want to make the band play "a piece" as soon as possible and feel at ease. There seem to be some teachers who repeat this mistake every year.
  The reason why there is a big difference in the level of bands every year even though there is not much difference in the amount of practice time depends on whether they practice according to this "obvious procedure".
  It is a "natural procedure" to teach letters first and then have them read sentences. The same goes for practicing an instrument.
  Just thinking about it, it would be a lot of work for a teacher to teach each part by mouth to 20 to 30 or more students who cannot read music, and it would be a waste of practice time with little benefit to the students.
  First, learn to play an instrument, learn to read music, and then practice a piece and participate in an ensemble is the "natural procedure". If you ignore this, you won't develop a good band.
  I think it is especially important for elementary school bands to practice reading music first, and then proceed with practicing the instrument according to the music that students can read.
  There are times in every school when teachers are unable to teach. At times like these, it makes a big difference whether students practice properly or not.
  If the content and order of practice are decided, the students can practice by themselves. If you decide on a leader for the whole group and a leader for each part, and make it a habit for the students to practice parts of pieces by themselves as long as they receive instructions from the teacher, they can practice more effectively.
  First, decide what you will practice each day and make a pattern for basic practice. I often see schools practicing the scales of these basic practice with the wrong notes (fingering). If you don't check the sound carefully at the beginning of each school year, students will repeat the same mistake many times throughout the year, so be careful.
  The impression of the performance is almost decided the moment the first note is played. In other words, if the tone of each member and the overall sound are not good, it cannot be called a good band. For that reason, especially in the first half of the school year, please use more than half of the practice time for sound creation (basic practice).
  Although it is not directly related to making sounds, instruct students to do various preparations and cleanup before and after practice by themselves as much as possible.
  It may be impatient to clear desks, line up chairs, set up percussions, etc., because it is much faster for the teacher to do it, especially at the beginning of the school year, but if you endure it and just give instructions, the students will gradually start to think and act on their own.
  Even if they can't set up large percussion in time, you get the other students to help and you should try not to move as much as possible.
  In the beginning of the first year of school, the band will not be able to do anything unless you give them instructions one by one, but they will soon be able to do it properly on their own. From the second year, the new students will watch the older students and move around.
  It's not important to set up, but it's important for the students to think for themselves and do things on their own.
  The same goes for preparation and practice. If you can raise students who can think and act for themselves, they will think about band practice for themselves, and this will be clearly reflected in their performance.