Stating straight up with dumbbells at your sides. Your palms should be facing your body. You should be holding the dumbbells slightly off your body, as this keeps the tension on the side delts. This is your starting position for the exercise.
To execute, slowly raise the dumbbells up to around shoulder height. Try not let your wrists go above your elbows while raising the weight, as this will take the work off the side delts and put it on the front delts.
Pause at the top of the movement, and then slowly lower the weight back to the starting position.