its basically all pratice
and what you use to keep your camera steady
well its 80% on your half and 10% on the equipment (what your using to hold the cam and keep it steady), 10% of what your skiing on (speed, conditions [smooth/gromers or chunky/bumby etc.).
cuz you have to have a really steady hand(s) and not be lazy, you have to lock your wrists and it helps keeping your arm dead strait ( i know its tryer but dont get lazy), and try to keep your upper body in the same spot and keep your legs loose