You have to get your upper body isolated from your lower body. This can be practiced right at home.
If you have seen a good martial artist moving you will notice a good bit of bend in the knees with the feet spread apart and the movements are a very "heel-to toe" or "toe to heel" (when backing) roll of the foot. The waist is slightly bent forward and the hips pivot at the waist so the upper body is like a turret. They keep the upper body more or less square to the threat.
Practice moving this way without the gun. Be like a duck...lots of movement below the water (waist) but smooth above.
Straight forward or backward are a simple "Ninja creep", mostly square to the target, heel to toe, rolling the foot and letting the upper body "float".
Sidways toward the strong hand: turn lower body slightly at the waist but keep upper body mostly square to threat. Same ninja creep and feet will almost cross in a crab like sideways movement.
Sideways toward weak hand: same posture as above but your feet will move in a motion more like backing up while crossing sideways.
Lastly, move in a circle about 4 or 5 feet around while keeping your upper body facing only one direction...pick a wall. This will force you to transition from forward to sideways to backward and then the opposite sideways movement and back to forward.
If you have a Glock, fill a shot glass almost full (use water in case you spill some
) and place it on top of the slide. Sight at anything you choose and move in each direction while keeping the sights on the target and without spilling the water. If you don't have a gun with a flat top, then hold the shot glass in your strong fist, grasping only the very bottom of the glass, achieve your two hand grip and sight across the top of the glass.
If you get too upright you will bounce and get wet.