SMOOTH throttle like Trill mentioned my first dump was from plipping the throttle and literally hopping my bike up off the ground and over backward. All in first gear.
IMO it would be best to learn simply how to clutch it or pop the front end in 1st gear then go to 2nd gear to learn the actual wheelie, 1st gear is touchy if your not sure of what your doing. In second you are going faster but there is more control as the throttle isnt as harsh as in 1st gear.