"Make sure you overcome what you are afraid of. Get Ready for emergencies~. Left hand first then right hand , then synchronize. If one thing is faster than the other, not so good" Also Heifetz taught his student - "Watch your left fingers while playing" When it was my turn to take a lesson in the class Heifetz told me to begin with certain scale and I didn't do a good job. And Heifetz told me no further lesson that day for me if I didn't practice the scales properly. Ever since that incident I practiced scales seriously. Thank you Mister Heifetz.