Originally Posted by
caloso
Get a fixed gear bike with mellow gearing (42x16=69, for example). Find a long gentle hill. Ride down it. Feel your feet spin like mad. Repeat until you spin the pedals instead of the pedals spinning you.
This doesn't always work as well as you might think. It's really easy to let your legs go limp and let gravity do the work for you which doesn't improve your cadence at all.
Rollers are much better, as is motor pacing while on a track bike.