There are many things that a musician should know, but there are 3 specific things that will send you beyond being mediocre. They might seem obvious, but it is their application that is crucial to your development.
This might seem like a pretty obvious thing for a musician. How else can you hear what is going on if you don’t listen? How many times has another member of the band asked how they played a particular section of a song, and the response was, “Oh, uh…I wasn’t paying attention.” If people said this during a conversation, we would be very irritated, but in a band setting it is easily brushed off. It takes practice to listen to the band as a whole and to what you are doing.
You can practice listening to your music in your car or on your headphones. Hear each instrument and practice isolating it from the rest of the music, then listen to everything and all the different sounds at once and note the way that the other instruments and sounds interact.
Learn your mistakes
You make mistakes. Why do you make mistakes? Many mistakes occur because of sloppy fundamentals. Remember that practice it wrong, you will learn it wrong. Identify you errors and fix it. Your friends are great at pointing out you flaws, so try not to take it personally.
Do not be afraid to invent your own technique or exercises. Imagine how the first person who ever played that instrument learned to play: there were no tutors or instructors for them. However, do not rehearse your drills! Change things up and modify your practice so that you do not become an expert in those little warm-ups.
Don’t Give Up!
Playing music is not an easy task. You alone are responsible for the way you sound. There is no shortcut or easy way to learn it all quickly. Determination is the greatest asset you have when playing. Sure you may have a limit to your abilities, but you can always be better than what you think.