To save on utilities….
I installed foam insulators behind all switches & outlets on outside walls & put a strip of latex foam insulation under the window frames & around the doors.
I made draft stoppers for the entrance doors using old jeans… I inserted one leg into the other, stuffed them with plastic grocery bags, and used a safety pin at the bottom of the legs & the top of the waist to keep the bags from falling out. We also hang a coat on the door handles when home to insulate the handle & block any draft not stopped by the foam strip.
I cut thick, solid foam that is used in construction (pink, 1 1/4″ thick) in 2 sections to fit the bedroom windows. Although not air tight they still provide extra insulation & it is balanced by the convenience of easy removal to open on nice days & being able to replace them at night in the winter or the reverse in the summer. (An added bonus is in the winter & once nights get hot in the summer it keeps the bedroom dark for sleeping.) On windows in other parts of the house I put plastic over them during the winter.
We use heavy blankets on the beds but also use mattress heaters to preheat the beds while brushing teeth & then turn the mattress heater off for the night. We keep our thermostat on 68 while home but turn down to 55 in the late evening.
When letting pets out we try to take them all out at once to minimize time the door is open.
We keep spare blankets/afghans in the family room & living room.
In the winter we use a dryer vent sold at hardware stores that can vent inside the house.
I dust mop the non-carpeted areas regularly to keep pet hair down & reduce the amount of vacuuming needed.