Firstly, you probably don't want to listen to this guy, unless you're his dog. Most likely the young blaster sounds like he looks. Posture and possibly attitude adjustments are needed. Conductor and potential colleagues just might have some serious reservations about his stage presence let alone his trumpet playing. This issue can be fixed instantly. Be careful. The visual matters.
Secondly, his daily approach should be organized for consistency. No shocking new insights here, just reviewing the time-tested steps to success that have always worked, but tend to get neglected. Make these a way of life. There will be no time on the big day to begin thinking about these. They must be habitual:
- Use an adequate air supply for each passage.
- Be able to sing the music accurately.
- Divide practice into many brief sessions for control of clarity, sound, and ease.
- Practicing slowly gives the brain and ears a chance to keep up. Help them out.
- Pause frequently to reset and refocus.
- Dynamics should be clearly discernible.
- Musical interest and style should be obvious.
- Incredible rhythm must be automatic.
- Intonation must be unobjectionable.
- Run-throughs ought to happen regularly.
- Be able to play faster than needed.
- Do even more run-throughs!
- Gain experience in different locations.
- Learn to "play cold".