Easy Tempo Music

How can I practice to play sixteenth notes faster?
Okay, I got some music that has lots of sixteenth notes, but i cant play them in tempo. the beginning of the song is easy for me, but when it gets to the sixteenth notes, i start slowing down. i slow down the metronome but it's either too slow and i speed up, or its not slow enough and i slow down. how can i practice getting faster?
if it helps, i play clarinet. if theres any technique to speed up, PLEASE tell me!
You can also try to identify the most difficult part of the 16th note passages, practice these first, very slowly and then speeding up gradually.
Break any difficult passage up into smaller patterns. Practice the notes slowly, identifying the difficult moves and first mastering them. Then play them in different rhythmic patterns, completely ignoring the original rhythm. When you can do this, try playing them backwards. Then play in the written order, but slowly and gradually increase your tempo. Make sure that you are breathing and phrasing in the correct places. Being short of breath can cause unnecessaryy mistakes.
When you start your practice of this piece, determine your starting tempo by first getting the difficult bits "under your fingers." Play the whole piece at this tempo and gradually increase the tempo for the whole piece.
Each new piece you get to play should have a challenging technique in it, this is how you develop your technique. You must first identify this new technique and master it slowly, so that it becomes second nature to you.
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