Try to connect your arm to the opposite side ribs in everything you practice-- forms, single movementÂ practice, resistance practice, push-hands, opening the car door, whatever.
The bones naturally spiral in such a way that the opposite side ribs are often more important for support and connection than the same side ribs are.Â When using both arms, this practice will give you the feeling that your arms are crossing on the inside--since each arm is extending and contracting from the opposite side ribs simultaneously.
It will also give you the feeling of having more leverage in push-hands because your arm is effectively longer. Enjoy.
Notice: In the picture from DKImages, the force goes from the left forward knuckle to the right side of the upper back.