You should be facing the direction in which the ball is coming from. Your hands should be straight and your legs slightly bent. You should be stable and well balanced.
Your eyes should always be on the ball. It may sound strange but keeping your eyes on the ball is perhaps the most important aspect of catching a softball. It is almost impossible to catch something if you are not looking at it.
Body Behind the Ball
Make sure that you keep your body behind the ball at all times. This is not possible at every play but try to do this as much as possible. It allows better balance when taking the catch and also adds cushion in case it is a tough catch.
When it is not possible to have your body behind the ball entirely, it is ideal that a clock position is maintained. If the ball is over your head, you can take it at a 12 o' clock position. When it is below the waste, take it at a 6 o' clock position. You can take the ones on the right at 9 o' clock and left ones on 3 o' clock positions.
Use Both Hands
Use both hands for catching. The glove will do most of the work for you but always use the other hand to make sure that you get ample support for the catch to be taken.
Never try to snatch the ball and instead let it come into your glove. This will help you in absorbing the jerk and as it comes in, firmly close your hand to complete the catch.