Does it seem like you’re always having to adjust by pushing in or pulling out? If so, you’re probably tuning based on individual notes.
The quick fix?
Tune according to trends, not according to individual notes.
What does that mean? When you tune, you should choose a few reliable notes on your clarinet (I like written low C, open G, middle C, and top line F on clarinet). Play these with a tuner and look for overall trends. If you are “trending” sharp, most or all of these notes are sharp. Conversely, if you are “trending” flat, most or all of your notes are flat.
If you adjust (pushing in or pulling out) based on individual notes, you might correct one note, but this could put several others out of tune.
By adjusting your clarinet based on a trend, your overall tuning will be more even.
It’s also important to note that the clarinet is an imperfect instrument, so there will be some notes which are pitchier than others. For these, check out my Complete Guide to Clarinet Tuning to see how to improve these.
Happy weekend, and happy practicing!