Top Lip

I pay very close attention to the way my students look when they play, and something that I recently started to notice in several of them led to a fairly quick improvement in their playing. I noticed that their top lip tended to actually rise up while ascending so that the apeture (opening in the lips) was at or above their top teeth. Basically, it was just being pushed around by the bottom lip and increasing mouthpiece pressure, so the size of the apeture was not really changing very much as the bottom lip pushed up. It is important to keep the top lip down in the airstream as you ascend. Even if you don't think that you are the extreme case that I described there is a good chance that you could benefit from a more active involvement by the top lip. I think that getting the top lip down into the airstream will be a big help in getting rid of the detrimental smile embouchure.