Work on your tensing up and relaxing of parts and in waves during the positions the four basics provide and see how you learn about the natural tension which holds you in place and how to work from it.

For example sitting with legs straight forward and an upright back, tensing everything and relaxing one part at a time with the breath of course.
Sitting at the bottom of the squat and tensing the left part on the inhale and moving the tension on the inhale, exhale from side to side.
staying in the static push up position and tensing up one part and with every breath move the tension around in the body always to one of the parts touching it as if you are moving a bit of tension around in the body and directing it.

Add this work when you are in the positions you usually work in such as sitting on a chair, prone with your riffle and so on.