Why can’t I spin a bo-staff like other people?
Once again, and I know I sound like a jerk here, but "bo-staff" is redundant. Also, you're conflating two entirely different delineations of martial arts, as the Monkey King used a bang staff, a shorter version of a standard gun (Chinese staff). If you were to learn Japanese techniques ("bo-jutsu") to cosplay as a Chinese character, it would be contradictory, but to the layman, I supposed it wouldn't make too much difference. Additionally, since you mention Darth Maul, Ed Park, the actor and martial artist to portray Maul, studies and trains in northern Shaolin, and for Maul, he used techniques associated with a more traditional gun. Onto the meat of the matter, though, you can't learn fancier techniques before you learn basics, even if it is just for show. I will say this: I have seen many people perform different variations of spins and twirls, but unfortunately, while doing so, they release their grips to assist with the spins. This is incorrect, as you would not want to risk letting go or dropping your weapon (unless intentional for rolling across the back of the hand, even that with regard to martial application...!). Essentially, it will take conditioning for wrist strength and flexibility in order to perform such moves properly. That comes with time and proper training. No short-cuts, sorry. EDIT: I just wanted to add that in my system, we do have a Monkey King staff set, but it predominantly uses a Yang style grip, meaning the hands face the same direction. The staff itself is also thicker, not tapered, and has more weight.
strong AND flexible wrists. You have to practice spinning and striking. Hard to learn from video and on your own. Also a lot of inherent bad habits.
What Anonymous said. It takes strong and flexible wrists. Check out some baton twirling instructionals too if you are just going for show.
You really, really don't want to get into learning this. It's for show, not actual combat. Having watched what some Americans now do with an ultra-light-weight aluminium 'Bo-Staff' which is nothing like a proper Bo, it's more akin to being a baton twirling cheerleader.....and it has no basis for use with-in the martial arts. My old Master used to say 'if it looks fancy, it's never going to work'.
Fun, but useless. If it's important to you, Darth Maul is using basic baton techniques.