Like learning to play piano or any other instrument, there are small drills / exercises that new students are often given to practice on in their spare time, to help improve their skills faster.

• Practice idling back and forth; do 50 or 100 repetitions of that. Whenever you ride, you always have to do this "idle to get comfortable" step, after mounting, and before moving away, so it's something you have to learn anyway. It also helps you get more comfortable with the unicycle generally, and more specifically, helps you learn how to keep the seatpost completely vertical, by helping you learn what it feels like when it starts going away-from-vertical.
• Ride "seat out", i.e. using your hands to control the seat, rather than your butt (this may be more intuitive to beginners, though obviously you eventually have to learn to control the seat with your butt instead)