I have a rule of thumb for my daily practice. 60% of my time is spent re-inforcing things I can do well. 40% is spent working on stuff I don't do so well. I make sure to keep up all the skills I'm good at, and hit hard things I have trouble doing after I'm confident the other skills are solid. Another way to think of it is to sound great for 60% (of course always sound the best possible) and then push the envelope the other 40%. I try to end with good sounding material as well, so the horn goes away when the confidence is high!