Position body so cable is at the side of your body. Stand in good body alignment (abs tight, chest up, back straight) with feet in comfortable position. Grip handle (top pulley) and position upper-arm perpendicular to the floor. Keep opposite arm stationary. In a controlled motion, keeping upper arm perpendicular to the floor, extend weight down, crossing the body. Contract triceps fully, without compromising form. While maintaining the controlled motion, return weight to starting position. Do not allow muscles to relax before next repetition.
Here are a few suggested alternative exercises:Ball Band French CurlBall Band Triceps KickBackBand KickBacksBand Overhead ExtensionBand Tricep ExtensionClose Grip Bench Press - BarbellClose Grip Dumbbell PressDecline Dumbbell Close GripDips - MachineDumbbell Lying ExtensionTricep Extension - Hammer Strength