Practice and practice. Test to move joints in different ways and see how you can get the most power. One way is to take left leg backwards and right leg forwards, right arm backwards and right rotate chest. Then test to move some other joints to make it better. Then space 2-3 times and totally rotate your body. Rotate chest left, right arm forwards, right leg forwards, left leg backwards. Aim for ukes torso and if you use the power the right way you will split him. You'll probably not succeed the first times you try.
Good luck.
Dodekus