I've spent three days watching trees dance in cold, whipping winds, and we had actual snow accumulation yesterday, along with icy rain. In this area, that's usually a month or two away - this is early! And next month will be colder. The Old Farmer's Almanac says we're in for a bit of a cold winter this year, and January will be the coldest. I don't want to pay as much as we did for last year's bills.
So, I'm doing more research on how to insulate our apartment. I've bought insulated curtains for DD's room, and picked up some socket/switch insulators. We've got a towel at the base of the front door until maintenance gets the door sweep fixed, and I plan on getting vinyl fabric to make a waterproof airlock curtain for the front hall. We've turned the heat down and eat more soup.
Putting a blanket on the water heater and insulating the pipes from it wouldn't hurt, either, but it's lower on the list. It's inside, so it's at least room temperature, but this will still help.
5 Ways to Insulate Your Windows for Winter at Apartment Therapy - a great site for anyone living in apartments!
Weatherizing Your Home: Weatherstripping
Resealable (Cat Proof) Magnetic Window Insulation Tutorial
Applying Temporary Insulation (video)