One of the most difficult tasks for tennis parents is finding the best coach for their children. There’s no shortage of good coaches, but not every good coach is right for every child, depending on age, ability and temperament. Unless you know a coach particularly well or have done a lot of research, it can be hard to choose the best person for your child’s advancement in tennis and, even more important, their happiness.

It helps to consider your child’s tennis development in stages. If you’re putting a young child into a tennis program, the most important thing is that the program is fun. A lot of painstaking details about technique are not necessary at this age. Lots of verbal instruction usually isn’t helpful either. Tennis is hard for beginners, so you want a high-energy instructor who invents fun games and makes your kids want to stick with the sport.

If you child gets hooked on tennis and really wants to improve, you need to make sure he or she has an instructor who teaches excellent fundamentals. This could be the same instructor you’ve been using, or it could be someone else. You could do both: Continue with fun group lessons, but supplement it with other lessons from an instructor with a track record for teaching strong technique.

So, how do you find a coach with the right expertise, especially if you don’t know much about tennis yourself? It’s no different from finding a first-rate home-improvement contractor or a top surgeon. Ask around. Check references. Talk to parents of children who have been with the instructor for years and get their views. Check to see if the instructor’s students stick with tennis and do well.

As a child, I was lucky to have Robert Lansdorp as a coach. Lansdorp is famous for being a difficult character, and I won’t deny that—he’s tough and gruff and loud. But I responded well to his sternness, because I was extremely driven. It’s important to remember that tough and negative are not the same thing. When Robert pushed me to my limits, I never felt as if he was being mean. I could see that he believed in me and wanted to bring out the best in me. I felt that he knew that I had more in me, and that’s  why he pushed me so hard.

There’s a lot more you can consider when evaluating a coach. First, watch their lessons so you can see first-hand whether both the coach and student are engaged and working well together. It’s good to have a coach who varies his or her routines, rather than one who works through the same drills and tips every lesson. This will make lessons more exciting and will add new elements to your child’s game.

Pay attention to how much interest a coach shows in your child. If a coach sends you a text message asking how a tournament went, or regularly follows up with you on your child’s progress, those are good signs. Here’s a good question to ask a prospective coach: What’s his or her philosophy on injuries and rest? Injuries and fatigue are important things to monitor in children. They’re not machines.

Last but not least, remember that success is relative, so choose a coach based on your child’s goals. If your child wants nothing more than to make the high school team and play two times a week, then an intense coach like Robert Lansdorp isn’t going to be a good fit. Know your child’s wishes, and you’ll know a lot more about what coach will work best.

Tracy Austin was coached by Robert Lansdorp, who has been credited for the development of Maria Sharapova and many other tennis greats.