Is a tennis ball machine better than a tennis coach?

As a parent how can I compliment my child's tennis coach, without interfering with development?

My child is 6 yo, is normal yellow ball good for her or his tennis development?

As a parent, can I teach my child? If so, how best to start?

What is an optimal way to make sure my child progresses exponentially?

How best to find a competent and cohesive coach for you or your child?

What are the common mistakes adult tennis learners do?

What can young kids do better in tennis class