Definitely some good advice being given to you here. Just like with any procedure, your reductions will get better with time and increased exposure.
Just a quick word of warning, though. You say that you were reducing a trimalleolar fracture that ultimately had the same appearance post-splint. I agree with the other posters.....this is an unstable fracture and very likely did move on you. The other possibility is sometimes you have a bony or cartilaginous fragment that impedes a proper reduction from being done. In any case, though....trimalleolar fractures that need to be reduced are generally done because a tibiotalar dislocation is present. Tread cautiously....if you're actually referring to a trimal fracture/dislocation that still looks about the same, the joint is dislocated. Go ahead and keep the splint on for comfort, but this one needs to be admitted for an urgent repair. (For those in residency....I know you're likely admitting all trimal fractures. This isn't always done in the community.) Be sure you're not discharging a dislocated joint.
Promise I'm not trying to question what you're seeing. Just a good discussion for residents to consider as well.