We probably cultivated our interest in music through listening to recordings and live performances. As musicians we want to engage ourselves in listening to music in the same way we would read a book or watch a movie. We can accomplish this by following along recordings with the score in hand. If you haven't attempted this before, it may take a while to be able to perform this kind of active listening, but is well worth the effort. You may wish to start by just keeping track of the measures as they go by rather than focusing directly on the pitches. With time your overall reading skills will improve.
Your choice of listening material should be quite diverse. Include pieces that you are practicing, and those that you are not. Explore many genres, instrumentals, composers, and style periods to broaden your understanding of music and help you generate new interpretations for your music.
You can enhance your concert experience by doing a little advanced preparation. If possible, listen to some recordings of the performers, and pieces on the program. Find out a little about the performers themselves such as their personal biographies, musical specialties, and musical training.
You can gain new insights into a piece that you are working on by studying the score. Outline and note its form, themes and the different keys that the piece moves through. You can also plan out your next practice session by identifying a particular section that needs work, or dividing the composition into different parts to aid in its memorization.
Spend time working on ear-training. Learning to sight sing, take musical dictation, and identify intervals and chords develops your internal ear, improves your sight reading skills, and facilitates learning new music.
Take a few months to learn the basics of a second instrument. Find an instrument that is completely different from the one you now play. If you play a melody instrument, develop some keyboard skills. Basic keyboard skills become essential if your musical studies involve any theory or composition. If you are a keyboardist already, try a wind or string instrument.
Finally, enjoy the learning process with a long-term perspective on your studies. Making music is rewarding lifetime pursuit whether as a professional or as an educated fan. Once you've mastered a few of the techniques we've just discussed, you'll find that you can take any spare time you have, whether a few minutes with your instrument or even without, and use it to help you become the musician you always knew you could be.
Small amounts of practice tend to be the most effective in helping you advance musically, shoot for 15-20 minutes of practice per day (no more than 30 to be sure) at music reading and music theory, and about 30-45 minutes per day of practice on your chosen instrument. Before long you'll be amazed at how much your musicianship has accelerated!