What one thing could you do every day that would improve your playing? Practice. This may seem obvious, but it can be hard to implement at times. It is far better to practice for 20 minutes a day, 7 days a week than for 3 hours one day. The math would make it seem like 3 hours (180 minutes) would be better than 20 minutes a day (140 minutes), but you will accomplish much more and progress much faster with daily practice.
So why is that? The more often you do something, the more natural it becomes. When you think of playing the fiddle, or any instrument for that matter, very little of it is “natural.” How you hold your bow, how you hold your violin, making an even sound with the bow… These are all things that you have to practice, and doing them more often helps the various components of the process to become more fluid and natural. Your body has muscle memory, and every time you practice these activities, your body remembers what to do, and it does not seem as foreign the next time.
The other reason that short practice sessions are more effective is because human beings are able to focus really well for a short period of time. When a person tries to focus for an overly long period they just start going through the motions, but are not actually improving and may in fact be introducing and practicing new mistakes.
I recently heard practicing compared to preparing for a marathon. If someone was going to run a marathon next year, that person would not decide to run 26 miles this week and then 26 miles a week before the marathon and think that they were prepared for it. The same is true with practicing.
Whether you are preparing for a lesson or a concert, having a regimen that includes daily practicing will speed you along your way!