Making quick stops is definitely the one to avoid when on slippery surfaces as the likely consequence is to be projected forward at the same speed as you were before stopping (inertia).
Skidding on slippery surfaces is often avoided when slowing down on curves or avoiding fast curves (the centrifugal force will push you to the outside of the curve and as faster you do the curve the stronger will be the push). Driving at a slower speed also helps control the inertia better (as faster you go, harder it is to stop when stopping is wanted or forced upon).
