Use a VMC #8 treble or a small Kahle hook and run it beneath the base of the horn near the (live) shrimps head. Use a popping cork with a leader of 2-5 feet depending on water depth, and with a large split shot about halfway down. The key is a smooth cast. Snap casting, like you would with a lure, guarantees the shrimp will fly off. You want to start w the rig in front of you, then smoothly swing back like you would for a golf or baseball swing. Swing forward smoothly, gradually accelerating, but aim you rod tip like you're hitting the golf ball or baseball pitch a few feet above your head and release when the rod tip is directly in front of you. It's the centrifugal force of the cork, weight, and shrimp turning through an arc that provides the power, not the bend in the rod. The type of rod is important- I use a 7-8 foot popping rod designed for 1/4-3/4 ounce weight.
Hook dead shrimp through the second section up from the tail. You won't get as many casts as from a live shrimp. Frozen shrimp is worthless- you're better off using a lure.