When waiting for the ball, your body should be centered. Your feet should be shoulder width apart, your knees slightly flexed, and both your hands in front of your body.
When at the baseline, your paddle should be facing straight, so the topmost edge is facing the net. The reason is you have plenty of time to decide if the incoming ball is going to be a forehand or backhand. When you are at the ‘kitchen’, in your ready position, your paddle should be in front of your body, and in a backhand position. When holding your paddle in a backhand position, you can cover all the balls hit at you and toward your backhand side (2/3 of the area in front of you). This will give you a higher probability to hit the next shot, especially if it is hit hard at you. Advanced players may hold their paddles when at the ‘kitchen’ facing the net because they are fast enough and know how to anticipate the ball so they can make that quick judgment whether the ball is coming to the forehand or backhand.