Here are some guidelines to help you stop safely on a slippery road.
1) Use your brakes judiciously and slowly when the wheels start to lose traction
2) Slow down as much as possible before braking (you should be able to see where the brake lights of cars ahead of you illuminate)
3) Avoid sudden steering inputs that can cause wheel spin
4) Turn on your headlights so other drivers know what is happening in front of them.
If all else fails try turning off your vehicle and then putting it back into gear if necessary; this might allow for better traction from being stationary. Remember these tips next time you find yourself driving on an icy or wet surface!