Imagine that you are sitting in a classroom. What would it be like if your math teacher was up in front teaching you advanced algebra, your English teacher to your right was covering MLA format, your history teacher to your left was discussing the origin of religion, and your gym teacher behind you was whistling for you to begin your next lap around the room? How nervous or crazy would it make you? About how much information would you retain?
It wasn’t an accident that we study one subject at a time in school. Our instructors and planners realized the importance of taking on concept at a time and giving our brains a chance to digest it. We can use this same principle and apply it towards our practice. If you need to work on your intonation, bowing, tempo, and shifting- don’t try to cover it all at once in the same piece! Practice each individual technique separately and master them through etudes or other drills if possible. Slowly start to integrate them together by going back to your trouble section(s) and using a metronome to bring the tempo down and gradually work your way up to pace.