Picture your ball sitting in wet, packed sand. To get out, do you think you have to swing harder and hit closer to the ball than you do when the sand is dry? If you are nodding yes, then you've got it wrong. When your ball finds wet sand, focus on two simple keys: 1) Swing easy and 2) Slap the sand.
Good shots from wet sand usually come out faster and fly farther than those hit from dry sand, so you need to swing easier. The danger is that if you set your clubface square at address, it might dig into the wet surface and get stuck--almost come to a stop.
Once you know that the clubface will not dig, the danger becomes the club bouncing too much and catching the ball thin. This is why you need to slap down on wet sand.
To see this in action, check out my wet-sand shot
Hit at about the same swing speed, my ball comes out much faster and will carry much farther, while both have ample backspin. Remember, swing easy enough to prevent hitting long and slap down firmly enough to get the clubface under the ball. Do that and your worries in wet sand will dry up.