Stand tall with your back straight, abs engaged, shoulders relaxed, arms at your sides, elbows bent and feet spaced wider than your hips, toes turned outward. Make fists with your hands and bring your hands up in front of your chin as if in "defense." Keep both feet on the floor and both elbows bent at all times.
Breathe deeply as you punch your right fist slightly upward and across the midline of your body (toward the left), while pivoting toward the left on the ball of your right foot. Pull your arm back down to the starting position, returning to face the front. Repeat uppercut punches on this arm (not pictured) OR alternate arms with each punch.
Every punch should have two phases: the punch itself and the retraction, where you pull the arm back down with as much effort as you took to punch upward. Try to remain relaxed in your shoulders. Punch with greater force and/or speed to increase your overall intensity.