all of it! Warming up, technicality, style, range, all of these areas on the trumpet are largely a thing of how you handle the trumpet mentally. I've seen people talk of the mentality of the thing with each area, and I find that it is true, more and more. Warming up: I just read someone posting agout warming up to an imaginary audience to enhance the warm-up. I've also seen people talking about a warm-up having little to do with actually warming up on the instrument. You spend some time thinking about the tone you want, what style you play, etc. Style: What do I need to say? You gotta feel it. Range: Up till about a few days ago, I could squeak a double C maybe once every year. My range was at a stand-still. However, listening to how the note sounds (and especially how my embouchure feels to play up there) has opened up the middle of the double range to me. Case in point: I've got a double C in the squeak mode. I don't really know how the D feels. I can't envision it in my mind, so I can't even bend the C any higher. It's all mental. Just as a trombone's altissimo range would be the middle of my range, I picture a brass instrument (that doesn't exist) up on the range scale, and figure "This note is just someone else's low note". Technicality: A little discourse I read of a teacher about "hard" pieces (at least, I don't think it was here...). What defines an "easy" piece? How familiar you are with it. Everything that I know that is "easy" is not necessarily easy: it is just familiar to me. So, you see a "hard" piece, and say "This is an unfamiliar piece. Time to familiarize myself with it." This seems to be helping me improve, anyway.