1.  Stuffy sound, forcing

• The trumpeter may be blowing too hard, using too much air, or physically trying too hard.  Encourage a relaxed body and an ease in playing, perhaps even a gentle approach.  Have the student look for a relaxed sound. Playing with ease should be a top priority.  Students should not move on to more difficult material until they can play the current material with physical ease.  Work only as hard as you need to and not any more.
• The trumpeter may be closing off the airstream with their lips.  Encourage the trumpeter to feel the air flowing across the inside fleshy part of the lips, allowing the air to flow freely into the mouthpiece.  To practice, have them blow air through the trumpet (with the mouthpiece inserted) and focus on how the air feels flowing freely through the lips.  Have the student blow air through the horn to the bell gently  (exercise borrowed from MWNA program designed to retrain brass players:  https://musicianswellness.com/).  Have them recreate this feeling playing the trumpet by playing low C’s with breath attacks.  Alternate back and forth between air and tone to match.

2.  Posture and holding the trumpet

Feet should be flat on the floor.  Shorter people can sit towards the edge of the seat.  Others can sit all the way back.  Shoulders, arms, and hands should be relaxed.  The trumpeter should be relaxed but not slouching. 

The left hand holds the trumpet, the right hand plays the trumpet.  The left-hand ring finger should be in the ring on the third valve slide.  The other fingers should be curled around the third valve casing and the slide.  The wrist should be as straight as possible and the ring finger should be as far out of the ring as possible.  The thumb should go in the first valve “crook” or in front of the first valve, at the bottom.  The trumpet should rest on the left hand.  The right-hand shape should be like holding a Big Mac or the shape of a backwards “C” (idea borrowed from Walter Chesnut).  The right-hand pinky should rest on top of the pinky hook.  The wrist should be as straight as possible.  The right-hand thumb should go in front of the first valve at the top.  Arms should be at a 90° angle. 

Good posture is important so that the air is as free flowing, in and out, as possible.  Proper holding of the trumpet is important for staying relaxed and for long-term physical health and comfort.  This can be difficult if the instrument is too big for the young student.  Be flexible with smaller students.   Using a cornet or pocket trumpet can help with this.  

3.  Tonguing, attacks, releases

Use the sound to guide articulation, or diction as labelled by Jan Kagarice. Tongue does not need to hit any surface in mouth but only needs to interrupt air/tone column. Tongue should time precisely with air movement. Tongue should interact with air part way back on the tongue. This location will move back as range increases.

A good analogy for tonguing is like a running faucet.  If you run your finger under the water, it does not stop the water.  The tongue should not stop the air.  The air should be continuous when legato tonguing; staccato tonguing should be one air flow even though it technically pauses in between notes.  

The energy in the air makes the sound, not the tongue.  The tongue provides color to the tone and helps with projection.  In most classical music, the tongue is not used to stop notes, just stop the air flow.