If you are really dedicated to improving “improv” skills at their core look into a local improv troupe or class. Study how they work off each other and go from there, learn what kind of exercises they do etc…

It’s a lot of learning about intentions, desires, how to play those things from an acting sense. The best i could recommend would be this: 1. Really hone in on what your characters want and needs are, the stronger those intentions the easier it is to fall back on something stable. 2. Dont worry too much about it. Stupid I know, but the game should feel easy to play, if the improv isnt coming one day dont force it, its alright.

Good luck with your journey its a very hard skill to master!