Here's a few things to try:

-change your shutter speed to 1/60 and adjust iris/aperture and iso to get the desired exposure
-change your output fps to 60fps, move the shutter to 1/120 and adjust iris/aperture and iso to get the desired exposure

That should help smooth it out the picture if the camera is stationary.

If you're handholding the camera, still do the above steps and also turn on the image stabilization or try using a gimbal or glidecam to steady the camera. If you're able to have a lens with built-in image stabilization, in conjuction with camera's built-in stabilization, and have all that on a gimbal, you will have the most stable handheld image possible.