Be sure the fireplace damper is closed when you're not using it. An open flue is like having a small window open; by keeping it closed, you can prevent around 8 percent of your home's heated air from escaping up the flue.
Whenever you can cut back on paper usage, no matter how small, it adds up over time. Select "no receipt" at the ATM machine when you withdraw cash; don't print out a boarding pass at home for your airline flight when you can send the boarding pass straight to your smart phone; e-mail yourself your grocery list instead of jotting it down on paper and read it off your phone instead. Little paperless decisions definitely add up.
If you're a crafter, avoid the temptation to buy cheap (and cheaply made) tools like scissors, cutting boards and glue guns at the discount store. Crafting supplies that break frequently end up costing more money in the long run and end up in the trash. One surprising place to find professional grade supplies is the hardware store for razor-sharp scissors, foolproof glue guns and much more.