There was a dance in the 1960s called "The Tighten Up" by Archie Bell and the Drells that topped both the pop and R&B charts in 1968.
But we're talking about a different type of tightening up here. You can take steps to "tighten-up" the insulation envelope of your house, improving a drafty, uncomfortable home that wastes energy. Sometimes the measures can be very inexpensive.
The first step is an energy audit of your home. But keep in mind that closing the air leaks is necessary. A 1/16th inch unsealed crack around a window lets in as much cold are as leaving the window open 1/2-inch. The chart below shows the locations that cold air can leak into or warm air leak out of your home.