There is something called The Alexander Technique that's an alternative therapy that concentrates on posture to relieve stress and a host of other health problems. I don't know much about it, but here's one little thing I learned that has been very helpful to me:
In technical passages, if you are flubbing a note, look at the finger you lift or put down immediately before fingering the note that you've been flubbing. If there's tension there, work on getting rid of it.
One example in which this has worked for me is doing a tremolo from high C# to D. The right D#/Eb pinky key is needed for most altissimo notes, but can't be used for the C# with most clarinets. it's not simple for me to play those two notes repeatedly and cleanly in the tremolo.
I found, using the technique monitoring the stress in my fingers, that my problem was tension in my RH the middle finger, not in fingering the D#/Eb key, so I work on that when that interval happens. That helped a lot.
Hasta luego.