2. Do not yell at them. Some parents resort to screaming at their children but its never a good strategy because it more often than not brings about a negative association to learning guitar.
3. Do not leave it up to them. Children learn best when they have support. Young children especially will rarely want to practice guitar if it means being sent to their room by themselves. If a parent sits with them and gets involved in a positive way you will see a far better result.
4. Do not just accept it. If your child is to succeed on guitar practice is essential so you need to be persistent in finding a solution. If you have tried everything then email me at firstname.lastname@example.org briefly explaining your situation.
5. Do not buy into their excuses. Children have plenty of free time so claiming they have no time for guitar practice is rarely if ever true. What they are probably saying is they don't feel like practicing and that's something that needs to be discussed.