A recent Fremont Motors post offers a number of tips for getting a cold car to warm up faster.
If the vehicle has an "auto" climate control setting, set the temperature to its hottest. This can be the fastest way to warm up the inside of a car. Otherwise, set the temperature to cold and turn off the fan. It seems odd, but it works. After driving for a while, turn the setting back to hot and turn the fan back on. This method works faster than setting the controls to hot with fan at full speed in a cold car.
Vehicles with a remote start will run for 10 minutes or so before shutting off if you let them idle. If your vehicle is in a garage, open the door before selecting remote start so dangerous fumes can escape. Although remote start can help warm up the vehicle, driving it warms it up more thoroughly.
A block heater warms the engine block and coolant for the coldest climates. Many of these have a timer and can warm the vehicle up for several hours before you're ready to drive.
Using an external windshield cover can also help make it easier to remove snow, if you park outside. This means you can drive away more quickly.