The majority of your practice time should be learning "how" to play the trumpet. Develop a practice schedule that will bring results. If you have 30 minutes to practice each day, 20 minutes should be on warm-ups, technique, lip slurs and scales. That leaves 10 minutes for solos, etc. If you have 60 minutes each day use the same proportions. If you have 2 hours, do the math and continue with the same proportions. The most important thing to remember is to REST as you practice. Play 10 minutes, rest five minutes and let your lip recover and yes, drink water as you practice. The point is that if you can physically play the trumpet, you can learn to play the music. One thing that I can not stress enough is to do Long Tones. We've all heard how important it is to play long tones and how good they are for us. With few exceptions I don't know anyone who does them (except for my students-"hopefully"). Trumpet player get bored too easily and rarely do them. So when you do your scales, do them in long tones. You will be doing two tasks in one.