I like your sentiments, but I think the advice could benefit from some more specifics that can guide the student / performer about how to think. To wit: For me the guidepost is honesty, and a willingness to focus on honesty with myself (and, when it isn't damaging, with others) both about things I already do well and about things I don't do well yet.So very true! This excellent comment makes me want to think further about this. While I agree with everything Robert is saying here, I think the problem is that it is difficult to be honest and objective about one's own strengths and weaknesses. As Marcel Proust observed in his great novel In Search of Lost Time, we come to know ourselves through others. This is why a good teacher is so important. I was blessed with some excellent teachers, but most of them were not very verbally articulate. I would have welcomed a lot more detailed commentary on the specifics -- and guidance as to how to evaluate my own playing.
Making sure I acknowledge to myself the things I do well gives me the courage to go on stage and do them, even in front of a room full of musicians any of whom I know could fill my shoes in the performance. And making sure I acknowledge to myself the things I don't do well yet gives me the capacity to set priorities in my practice, without negative self-judgment.
Once we reach a certain level of skill, every one of us has something musical to offer to our listeners, and for each of us some aspect of our offering is unique and cannot be duplicated by anyone else. This is a very helpful thing for me to remember when I am focused on my weaknesses, because it reminds me that:
o) everyone has weaknesses;
o) I have strengths;
o) I have the power to diminish my weaknesses and grow my strengths through practice; and
o) despite my weaknesses, my strengths are worth sharing with listeners today, just as they are right now.
I was simply blown away on one occasion when my girlfriend, a harpsichordist, was getting comments from one of the judges on her senior recital. The judge, one of three, was a Dominican monk whose specialty was the harpsichord and I recall standing in the hallway after the concert while he made incredibly detailed comments. An example: "in measure 8 of the courante, you should try filling in the third of chord on the second beat. Why not overdot the following measure and hold back a bit on the cadence?" And so forth. It was as if he had, not a photographic memory, but a "magnetic tape" memory! He could recall so many details of the interpretation. He was holding up a mirror to my girlfriend. It is through many experiences like this that one receives guidance as to one's own playing.
Guitar teachers, on the whole, at least when I was a student, were very bad at this sort of thing. At best they might offer very generalized comments. I can recall playing the whole of the 4th Lute Suite (the prelude of which, played by John Williams, I put up as an example on my previous post on self-criticism) in a lesson at McGill once and my teacher had scarcely two words to say. As it was the first time I had played it for him and I had spent some weeks memorizing it, this depressed me. I couldn't help but think that there was something wrong with my playing and he just didn't want to tell me! In reality, he was probably just feeling jealous and resentful because he was not a very good Bach player. I couldn't have thought that at the time, but in retrospect, it is very likely.
A good student needs a good teacher. This is obvious. But good teachers are really pretty rare. If you are a student--at whatever age--it is worth it to expend a lot of effort to find a good teacher. Because of your inexperience it may be difficult to know what to look for, but try out a few different teachers and compare their styles.
A good teacher is supportive and confidence-building. They also offer detailed comments and critiques on your playing and detailed suggestions as to what to do to improve. They do not lose their temper and yell at you! Some may not offer so much verbal commentary as played commentary. A good teacher might not say a word sometimes, but just play the piece themselves as a model.
As you advance as a player, you will undoubtedly get to the stage Robert is talking about, where you can make useful evaluations of your own strengths and weaknesses. Now let's listen to some good playing! Here is Manuel Barrueco playing all of the 4th Lute Suite by J. S. Bach: