Just taking the time to caulk all your windows and around all vents.
Will help but if you want to save money then you will need to check your foundation in the basement mack sure that the rim is insulated and plastic covered.
Using can foam to fill in large holes and spaces will help as well. You should check to make sure your attic hatch has weather stripping you can also check to see if your attic insulation is up to par it should be 18" deep.
Adding insulation can be done buy add Batts or renting blower and doing it yourself, if you hire a company they will make sure it is done right and add venting if needed.
This is a good time to have your heating system checked and serviced.
If your home is older it could be that you can look at having spray from install to fill in the cavities of your walls.
Your windows might need to be replaced if there are not thermal Payne.
Some homes might need to be stripped on the outside then you can strap the outside spray foam and and siding to get the desired insulation value.
There are many ways to make your home ready for winter these were just a few remember that the more you do to stop heat loss the more money you save and warmer you stay.
