It's no use practicing too much. First you have to find out how to do it best. You have to be able to invent ways of doing better. Not only practice; obviously you have to practice. But to invent things how to do better. If somebody doesn't know what invention means, he should stop violin playing! You can't explain everything. . . Not practicing only: Think how to achieve quality.
The folks you help won't remember it and the folks you hurt won't ever forget it.