I'll jump in and say that RSpears is mostly correct, I'd add that before setting the choke, you should push the throttle pedal about halfway down and hold it there, then pull the choke out fully. This will let the cold idle cam come into play and hold you're idle at a higher rate of rpm..

Once the choke is fully set, crank the engine and once it starts push in the choke handle to allow air into the engine, again you'll need to find that sweet spot RSpears talked about, it's just that now you're engine should be at a higher rpm allowing it to warm up faster.

Once the engine starts and you've begun pushing in the choke handle, the engine will rev high until you step onto the throttle which will allow the high idle cam to come off.

And of course the caveat is this will all work as long as no-one has backed off the adjusting screw for the high idle! HTH!