This is an oldie but a goodie and a golf tip you may have already heard of.
Imagine there is a rectangle around the golf ball or alternatively that there is a $1 bill underneath the ball and you are going to aim to take the amount of sand within the rectangle or the dollar bill.
The sand wedge is designed to hit the sand and shallow out rather than dig into the sand and this dollar bill visual can help you achieve this when you play your bunker shots.