When you are pursuing any amount of technical ability on a musical instrument, there is no substitute for hard work. Hard work, though isn’t enough. Once you identify the skills you want to work on, you have to develop those skills through repetition.
After all, drumming has a huge physical component to it: the mechanics of the player’s hands, arms and fingers, posture, relaxation, grip…the list goes on and on. Those aspects of a student’s playing are refined through repetition, which is a decidedly unglamorous thing to talk about, but it is indeed the key to greatness.
Repetition with purpose is your greatest ally when you are studying drums, guitar, violin, or any other endeavor really. Mindless repetition is dangerous - you can reinforce bad habits, which will push you further away from your goals. Repetition with purpose is the best thing a student can do in order to build up dexterity and confidence with a complicated passage in a chart, or a sticking combination that might be somewhat unfamiliar, or a drum set fill from a Motown song from back in the day.