-See if exterior doors close tightly: Do they sag? Do they rub their door frames? Are latch plates or hinges loose? If the answer is "yes" to any of these questions, spend some sweat equity to straighten the way your doors hang.
-Replace worn-out weatherstriping. If you can't find exact replacements, spring plastic strips, V-strips, or tubular gaskets make good alternatives.
-Repair air leaks around windows. On a windy day, use a lighted candle to find air infiltration. Make sure storm windows are in place. Fix broken caulk around window exterior. Replace broken weatherstriping. On old leaky windows, consider using plastic sheet insulator kits.
-Remove debris from window wells.
-Remove leaves and twigs from gutters, downspouts, and leaf strainers.
-Check storm drains for debris.
-Examine your foundation for signs of termites.