General Warm Up
A good warm up is to play chromatic scales. Start on a concert Bb, Play down to the lowest note you can hit. Start on a concert Bb again and play up to the highest note you can hit.
A chromatic scale is a scale in which every note between the starting and ending note is played. This means if you started on a concert Bb playing up to a concert F, you would play the concert Bb, concert B, concert C, concert C#, concert D, concert D#, concert E, and concert F.
It's also important that you play the scale corresponding to a piece's key signature before playing the piece. For example, if a piece you are going to play is in concert Eb, it is a good idea to play a concert Eb scale in your warm up. Scales can be found on the Scales page.
A chromatic scale is a scale in which every note between the starting and ending note is played. This means if you started on a concert Bb playing up to a concert F, you would play the concert Bb, concert B, concert C, concert C#, concert D, concert D#, concert E, and concert F.
It's also important that you play the scale corresponding to a piece's key signature before playing the piece. For example, if a piece you are going to play is in concert Eb, it is a good idea to play a concert Eb scale in your warm up. Scales can be found on the Scales page.