If you haven't calibrated lately, that's your first step. Then in map controllers on your clipboard, hit the Y axis and click on enable scaling. Add in a small amount of deadband, which will keep things from moving if your stick's center is vague. Repeat for the X axis. I also did this for the twist rudder to cut down on unintended rudder inputs. You can also experiment with the scaling sliders to make your stick less squirrely, though this can make your stick feel less responsive.
