The biggest struggle with learning a new instrument is finding time to practice. I think practicing an instrument is similar to exercise–once you get into a rhythm it becomes a daily necessity. As a teacher I have noticed that some parents see lessons as a substitute for focused, daily practice. While putting your child into music lessons is the first step to learning an instrument, the benefits of learning music will not be gained without a strict practicing schedule.
5. That 10,000 Hours Thing
There is something to Malcolm Gladwell's book about how an expert is someone who has spent 10,000 hours working on something. Putting the time in certainly increases the chances that your child will excel earlier than others, making the more advanced parts of playing the violin easier. It can take about 10,000 hours before the instrument "sounds good", so be prepared for some screechy violin sounds until then. (or buy a practice mute!)
4. Young Children are More Agreeable (for the most part)
Learning technique is tough, tweens are also tough; mixing them together can be a recipe for disaster when learning an instrument. Get the basics over when a child is young and asking to learn the instrument so that when they're older most of the hard work is behind them. Make sure your teacher mixes in learning technique with fun songs they're excited to learn so that it doesn't become boring. It is also really helpful if parents can sit in on lessons for the first year and assist their children with the practicing at home; most likely after the first year the student won't need your help anymore.
3. Practice Habits = Homework Habits
Teaching your young child about the importance of practice will reverberate through the rest of their life and give them a strong sense of structure. Children crave structure and challenges, music lessons provide that in abundance. There is a strong link between intelligence and higher grades with students who play a classical instrument; I don't believe that playing an instrument passively creates this connection. It is developing good practice habits that makes the connection with homework habits, not just playing an instrument. Make sure your teacher has a method that continues to challenge your child's learning, whether that is their own method or something widely recognized like Suzuki.
2. Hard Work Pays Off
When a child puts in the hard work and sees a positive outcome it will create a link between practice and reward. Find reward systems that clearly connect practicing with good outcomes that they will appreciate. Students may also love thinking of practicing as their "job", ten minutes of practice can equal time playing video games, watching TV or even just beans in a jar that will equal a new toy. Eventually playing will become easier and more fun, and that will also encourage good practicing habits. Ask your teacher to create goals for your child to inspire them, like recitals, competitions, and festival orchestras.
1. We Learn Habits Early
Think about the behaviors you have as an adult. Some of us bite our nails, or say "I'm sorry" too often; these are behaviors we learned very young and are hard to expel from our brains. I find that when a student learns practicing habits at a young age they will not need their parents to push them as they get older, taking on the responsibility themselves. When that light turns on the student becomes inspired on their own. A parents initial effort in encouraging practicing provides a child with a better long-term outcome with the instrument. It also is important to learn the basics of the instruments technique as early as possible so that bad performing habits don't persist into adulthood.
This article on NPR's Deceptive Cadence discusses different positive reinforcement reward systems with testimonials from children who grew up taking ownership over their own practice habits.