If you haven't seen it, there's a great article in this quarter's American Suzuki Journal (Vol. 39, #4) by Benjamin Wyatt about the use of counting beads as a practicing tool, and it got me thinking about the subject of repetition.
We know that repetition (and lots of it) is the key to skill development. Particularly when a skill is new, a child must repeat it many, many times before it feels easy enough that he is ready to add another layer of complexity. Beyond that, Dr. Suzuki said it takes 10,000 repetitions before a skill is mastered (i.e. as deeply engrained as walking or speaking in the native language). Most of those repetitions happen during the practice of review repertoire. But it's important not to underestimate the number of repetitions that are needed at the early stages of learning a new task. There is a plethora of ideas available for how to motivate a child to repeat a task many times, so I won't go into it in this post (see here), but it occurs to me that perhaps more needs to be said about figuring out what to repeat and how to repeat it.
1. One thing at a time. Avoid asking the child to think about several things at once.
2. Pick a chunk of music that your child can play successfully. If there are mistakes, you are trying to do too much, or the tempo is too fast. Break it down further and/or slow it down. In most cases, the smaller the chunk the better. (It's too much to ask your bk. 1 child to play Go Tell Aunt Rhody ten times in one practice session. It is probably not to much to ask him to play the first measure ten times with the bow distribution his teacher showed him - but it might be, in which case, ask him to play the first note with as much bow as the teacher asked for, then add another note or two, etc.).
3. Clearly identify what criteria must be met to count a repetition as successful, make sure the child understands those criteria, and evaluate the repetitions fairly based on those criteria.
4. Involve the child in that evaluation process.
5. Make sure your child stops completely between repetitions, and carefully prepares for each subsequent repetition.
6.Repeat a skill as many times as necessary to make it easy BUT a finite number of times in one practice session. Set attainable goals (e.g. 7 good tries in a row) and when that goal is met, move on. If you feel that the child needs more repetitions (and she almost certainly will), include them in the following day's practice. Children get frustrated and impatient when a task seems open ended.