Work on pushing without tensing up by using your breath as the wave and by letting the movement come from your body as one unit, but relaxed so there is no attempt to keep a certain shape despite your senses telling you it’s a bad idea
Fall on your fists and let the movement pass onward.
Have a partner place his hands on your shoulders and close his eyes. You need to strike him and if he feels you are moving before the strike hits in, he slaps you in the face.

Smile, it relaxes the face and than the rest relaxes.

Remember that learning to take strikes and survive is more important than learning to strike deep. They are connected of course.