I don't know how to say these things other than directly. (Well, I probably could...but I won't):
If you need to look at your music most the time and not the conductor, you don't know your part well enough (or don't have enough confidence that you do).
THE major fault of most players in ensembles is that they have their noses buried in their parts and don't pay enough attention to the conductor. Practice your parts on your own so that you can look away from the page and know what the conductor is doing. Rehearsals and performances are not practice sessions. That you flub notes or even passages isn't as important as being in sync with the conductor and therefore the ensemble.
Another major fault of most players in ensembles is that they concentrate on what they are doing instead of concentrating on what the section and the people around them are doing. If you're stuck looking at the page for every note, you don't know your part well enough. If you're so wrapped up in the page in front of you and not constantly listening to the ensemble and the people around you and adjusting your playing, you are hurting the ensemble.
Another major fault of many players in ensembles is they insist on playing every note even if they risk falling behind instead of leaving a note, a few notes, or a cluster of notes out to keep up.
Another major fault of many players in ensembles is that they insist on tonguing every note in a fast articulated passage even if they risk falling behind instead of adding slurs or leaving out notes.
It's impossible to hide by playing too quietly. Either someone will hear you or someone will think you're playing too quietly. Regardless, they'll know that you're playing. One way or the other, you can't hide, and you're penalizing the section with your timidity.
THE major fault of amateur players when they practice is that they never practice slow enough, very gradually increasing the speed, but continue to run through passages at full speed, practicing the mistakes and usually making new ones. (When I'm teaching, probably my most often repeated instruction is, "SLOWER!")
The difference between an amateur and professional is that amateurs practice until they don't make any mistakes, but professionals practice until they can't make mistakes; they know their parts too well. (Well, this isn't always true, though it's something to shoot for. Professionals have their "yips" like the rest of us, but they are almost always less frequent and rarely because of inadequate preparation.)
Your clarinet tells you how it wants to be played. If you try to force the clarinet to play the way you want it to, it will rebel. You can either change your playing or you can find another instrument that agrees with you. (Good luck with that!)
After a certain point of skill development, problems in playing are mostly psychological, not a matter of inability. (A subject for a future article.)
The slower the passage, the more likely you'll rush.
The faster the passage, the more likely you'll rush.
It's better to play slower and make music than it is to play faster and make noise.
Practicing like crazy before a performance right up the downbeat will do you no good. If you don't know the piece by that time, getting all bent out of shape trying to muscle your way into playing it correctly won't work, and you're likely to just be practicing your mistakes. Better to take a day, two days, or whatever after your last practice session and before the performance. You'll be calmer and you'll almost surely play better than if you flogged away at the music right up until the downbeat.
In solo playing, play the music, don't play the instructions on the page. Aside from the fact that the instructions on the page may have been put in by an editor and not the composer, unless you're afraid that the Clarinet Police will arrest you for deviance, your job is to make music, not follow a blueprint (though some academics will strongly insist otherwise). The late Leon Russianoff, probably the most famous of all clarinet teachers in the modern era, would have his students erase or cover up all the tempo markings, dynamic markings, articulations, and so forth and play according to what they "heard" themselves.
There's a vast difference between playing notes and playing music.
End of brain dump.
Cheers!
B.