"If you detect air leaks around their perimeters, seal them with weatherstripping, caulk, or a combination of the two." Original Source: http://www.bobvila.com/slideshow/don-t-make-these-7-mistakes-prepping-your-home-for-winter-50609/4-don-t-underestimate-creosote?bvsp=lg
Homeowners tend not to appreciate that their gutters, by channeling storm water away from the home, perform a pivotal function. If you expect your gutters to do their job, you must first clear out any accumulated debris that could eventually clog and compromise the drainage system. In addition to ensuring problem-free performance at peak efficiency, regular service also helps the furnace fulfill its estimated useful life expectancy. The HVAC technician should inspect each furnace component individually, making repairs as necessary, while also cleaning or replacing the filter. As the furnace filter goes a long way toward supporting indoor air quality and protecting the internal workings of the furnace itself, the technician may suggest that you clean or replace the filter on your own, perhaps as often as every three months. Be sure to ask. As much as homeowners fear the prospect of a frozen pipe, many forget all about the fixture most at risk—the outdoor hose faucet. Nowadays, it's easy to protect it. Simply purchase a low-cost cover to block cold air from reaching the faucet. Or better yet, install a brand-new outdoor faucet that's specially designed not to freeze. Of course, in a pinch, you can also do it the old-fashioned way: Locate and close the water shutoff valve along the line that supplies water to the outdoors. Then, to complete the process, open the faucet to clear out any remaining water. if you see branches scraping against your home's roof or exterior siding, cut them back to a distance of at least three feet. KEY TAKEAWAYS:
Don't disregard your gutters.
Don't omit outdoor faucets.
Don't trifle with trees.