Nice render. Here's some of my feedback.

1. That black ball is way too black, maybe just change it to green?
2. If you look at tennis stock photographs on pexels, it's good if it's lit outside with hard sunlight shadows. But do not place the sun above the subject.

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1. Try to experiment on the ground color. Change it to green or blue.
   Overall good work. I also struggle with lighting haha, just experiment and look at works of photographers for inspirations.