Focus on reading the server's position to anticipate the ball trajectory, make quick decisions on how to play the return (using one or two walls), and utilize a short backswing with a continental grip for better control and timing.
This is a very helpful lesson if you struggle returning serves that hit the sidewall. Sven explains that returning sidewall serves is easier than you think if you understand the key principles. He breaks down the return into reading the ball, making quick decisions, and using proper technique. Understanding these elements will definitely improve your confidence when facing serves that go towards the side glass.