First thing you have to do is get familiar with all the joints which I did in single player. Then you gotta work on finding an opener that works for you and start understanding how to win matches. Then once you start winning u gotta step out of you comfort zone and mix it up. I would select random joints to start and go from there.
After words around my first black belt I created the scissor sweep and that was my only move for like a year. Fast forward to now with team aikido and well we know how that goes.