The ability to produce backspin (slice) on dinks, returns, and drops. Slice creates a floating ball flight with a low bounce, making it an essential tool for cross-court dink exchanges and a natural counter to incoming topspin.
Use a continental grip or close to it. Keep the paddle face open and the paddle head at roughly a right angle with the forearm. Use a minimal backswing and push through with the shoulder, avoiding breaking the angles created at the wrist and elbow. Follow through toward the target. The motion is a controlled forward push, not a chopping action. Contact is made slightly above center of the ball with the paddle moving forward and slightly downward.
Morgan Evans lists the slice dink down the line as one of "5 shots hurting your game." To generate meaningful spin on a slice, you need paddle acceleration. But the down-the-line window is only 7-10 feet — not enough distance for the spin to do anything useful. You accelerate for spin, the ball travels too fast for the short distance, and it pops up or sails. Better options: drop the paddle head and take it early as a volley or half-volley, eliminating the need for spin altogether.