Even anime needs structure. If you can work on mannequins, you can build your structure(seen in red) then on top of the structure, build your anime anatomy. I’d practice drawing mannequin poses until they become natural and then try to gradually add your detail. Hope this helps give you some things to practice.
the mannequin pass is solid, maybe also lean the torso into the hit and let the fist overshoot the dragon a bit so the punch reads past the target instead of stopping on it

