Perfect Example of The Low Breath

From master high note artist Jim Manley. In 10 minutes he changed my playing world upside down, or more appropriately, right side up.

The 2 Golden Rules

There are two rules that are fundamental to trumpet playing:

1. The Low Breath - Stick your finger about an inch below your belly button (if you have one). Push your finger outward with your belly, perpendicular to your body. You should feel your guts shift. Combine this with dropping your jaw (thus opening your mouth) and for a while this will be the only way you must breathe.
2. High Notes = Fast Air (smaller volume)/Low Notes = Slow Air(larger volume) - Don't confuse air speed and volume of air! The simplest way to execute this is to imagine a target (bullseye, candle, etc.); the closer the target to you, the lower the note and vice versa.
   

While there is certainly more to playing the trumpet than these two rules, the internalization of these two things will eliminate or prevent bad habits. I will expand on these later.