I'd just add four things. 1. Familiarity with the style and rhythms, 2. The ability to look at a page of music and understand what you need to do (Dynamics, range, etc.), 3. Key changes ('nuff said), 4. Automagically know what valves to press for the note of the moment.

Oh, and, being able to count to 4. ;)

When a piece is put in front of you, scan it so that you know what's coming.

Always read ahead.

Ok, I guess that's 6 or 7 things.

Dave
www.youramerica.net