When I'm home, I practice four or five hours a day...I warm up for an hour before a gig.
The main problem is to free your mind when you play. I find that in my own playing, whenever I feel any kind of tension, I'm restricted to playing the most fundamental kinds of things.
Economy: that what you played had to have meaning, not just a bunch of sixteenth notes. You learn to make better choices of notes as you get older.