Since heaters often dry out the house and leave it void of humidity, placing a humidifier in commonly used rooms can help make them nice and cozy. Don't increase the humidity too much, though. You don't want your house to turn into Florida.
Seal the Deal: Cracks, no matter how small, are a great way for Old Man Winter to sneak into your house. For this reason, using sealant, caulk, and storm windows is imperative. You want to keep heat in, not try to heat the whole neighborhood.
It's also a good idea to leave your drapes and curtains open during the day. The heat from the sun can help keep your house naturally warm.
Get an Electronic Thermostat: These days, most thermostats are electronic. If you have an old one or live in an old house, your thermostat may be a little outdated.
Because electronic thermostats are programmable to adjust to temperature fluctuations, you can spare yourself extra degrees, and extra billing, by using one. If yours is outdated and not electronic or not programmable, then simply get a new one – stat!