Unlike more traditional martial arts, which have highly regimented curricula and skills that must be learned and demonstrated for each successive rank advancement, Thaiboxing and Jiu Jitsu are more performance based.
You either can, or cannot, execute the skill against your opponent.
As such, it can be difficult to know where to invest your time and energy. There are just so many different skills to learn!
Generally speaking, find your biggest weakness, or the most difficult skill, and make it your strength. Orient yourself in that direction and move forward.
Can’t check a leg kick? Become unkickable.
Can’t pass a guard? Practice until there is no guard you can’t pass.
And so on.
Leap frogging your worst skills to the front creates natural progress towards effective performance.
So when you inevitably run into incredible difficulty somewhere, don’t despair. Be happy! You just found the next stepping stone on the path to excellence.