When you first learn how to play a sport, such as baseball, it is important to take your time and practice the basic skills to become acquainted. Playing catch with a tennis ball allows players to practice the art of catching and throwing a ball. A tennis ball is much softer and lighter than a baseball, and will frequently not hurt if caught improperly. Once you have the basic mechanics down of how to catch a tennis ball, you can start using a real baseball.
Keep your eye on the tennis ball. Watching the ball keeps you prepared for it as it comes your way. It also increases your hand-eye coordination as you watch the ball come toward your hands.
Move with the ball. It’s much easier to catch a tennis ball coming toward you if it is aimed for your chest or the centre of your body. This complements keeping your eye on the ball. If the ball is to your left or right, it becomes much more difficult to watch the ball meet your hands. It is also more difficult to account for changes in the ball’s direction.
Use both hands to catch the ball. Using two hands allows you to use your secondary hand to help clasp the ball and eliminate any chance of dropping the ball. This is important whether or not you are wearing a baseball glove to field the ball. When you are wearing a glove, use your non-gloved hand to support the glove and clasp it closed.
Keep yourself in "ready" position—knees slightly bent as if squatting, arms in front of your chest and palms facing outward. If your body is ready to field the tennis ball, you are much more likely to catch the ball. You don’t want to be caught off-guard and have to twist your body to a field position—you may lose sight of the ball, lose your balance and ultimately drop the ball.