Turn off the heat. DO NOT turn it back on UNLESS it snows and even then I am frowning if you do.
Walk every day. Walk the block, walk a mile, walk something. UNLESS it snows walk. Or if it is icy. Don't want you to break your tailbone like I did. It makes walking way not fun.
Grown Up Tightwad:
Do both of the above AND downgrade your source of entertainment. Be it Cable, Satellite, Netflix, going to the movies... lessen it by at least $10. Maintain that lessening forever.
As for me... I'm doing all of that AND I am gearing up for the garage sale we are going to have in a month or so. Yay! Dejunking!