I would start by turning off the water to the outside. And then drain the water out of the hose if there is one attached. I do this so that the chances of a pipe freezing are minimal. Because, if one does freeze in the spring it will most likely start leaking.
The second thing I would do is get the plastic for the windows. Even in new houses drafts can still come through. On the packaging it says it can reduce your heating bill substantially.
Another thing is to grab some adhesive foam stripes for the doors. Put them on the top and side of the door to eliminate drafts, and to provide an air tight seal.
Change the filter in your furnace so it can blow more hot air better. Close the doors, and or heating ducks to rooms that you don't go into very often.
Another thing that might help is to grab a space heater, and turn the furnace in the house down to around 65-70. It will save in the long run, and keep you warm.
Not much else I can think of right now.