I recently watched a French movie about a music teacher/student relationship. The movie's title is Tous les matins du monde (All the World's Mornings.) The movie is about a young would be musician looking to study with a great master. The movie is a bit to complicated to relate here but it boils down to the lessons learned that turn the young student into a great musician. One of my favorite scenes involves the master telling the student his fingers work wonderfully, he plays no wrong notes, but he'll never be a musician and no amount of practice will change that. He tells the young student that he'll never reach an audience. Pretty harsh criticism but I see his point. Music is an expression. As the movie beautifully states, "music says words that we are unable to speak." The student had no feeling in his playing. You can't teach that.
One of my favorite musicians is always saying "play what you feel." This is the best advice. We're attracted to the sound of music for all kinds of different reasons but surely it comes down to the way it makes us feel. Hard to define but undeniable. I like to spend extra time working with students technical problems because I feel that they need extra help on that subject. If we're limited technically we'll be unable to get the music out. This is indeed important, but I have some new advice to go along with that. Whatever you play feel it.
A couple of years ago I competed in a guitar competition. A competition based on music is kind of ridiculous. Music is art. Very subjective. However, the competition was a very good learning experience for me and I'm glad I did it. Most of the contestants (me included) tried to play fast and sound impressive with little emotion other than trying to show off. One contestant however played very slow and expressively. She made few mistakes and in my opinion had one of the most musical performances of any of the contestants. Even though she didn't win her performance got her into 5th place and the memory of her playing has stayed with me. I couldn't tell you what anyone else did. She played with great feeling and a minimum of flash but it didn't matter. This was great music.
Work on your technical problems. Practice, practice, practice. By all means go slow, but remember why you're playing. Get into the music. Play what you feel then feel what you play.