This may dampen my claims a little, but I roller skate (inline) and play tennis. And I wouldn't say I'm great at either, so maybe it's just because there's a lot of clear air above me that I'm able to make noticeable improvements.
However, I've needed a target in order to make those improvements. For roller skating it was skating backwards, and for tennis it was changing (correcting) my forehand grip.
With tennis it's been 12+ months of inconsistent hitting (including losing a grand final game 0-9 playing almost the worst tennis of my life) before I really started consistently being "better". There was a valley separating where I was from where I wanted to be, the depths of which had to be trudged through.
With inlines it was one of those situations where it feels like no progress is being made for a long time and then it all clicks quite suddenly. It took me about 18 months to go from tentatively rolling backwards after pushing off from the wall to can satisfactorily speed skate backwards.
Gotta have a target, gotta commit to crossing the valley.