Be patient and don't use your arms. Let the boat pull you up. Keep your skis pointed toward the boat and at a 45-degree angle with the water. Learn proper body position. Keep both ankles bent, which forces the front and back knees to work as shock absorbers.
Most people use their knees and butt, but the ankles and knees are the absorbers.
Practice a proper stroke. Freestyle is the most commonly used stroke, and can be done for the longest time most efficiently, but Selz suggests learning additional strokes to improve balance. To slalom, first determine which foot goes in front. On land, have a friend stand behind you and gently push you forward. Whichever foot steps forward will be your front foot.