Inspect and clean the tracks. Grease, dirt, and debris gum up the track and prevent the door from closing properly. Dampen a rag with paint thinner and clean the tracks.
Lubricate all the moving parts with a lightweight oil. Lubricate the rollers and hinges. Wipe the cables and cable pulley with an oiled rag.
Raise the door and check the condition of the weatherstrip on the bottom of the door. If it is worn out it needs to be replaced. Use a hammer to pry the nails out of the old weatherstrip. Slide it out of the track. Buy weatherstrip designed for garage door seals. Measure the new piece to fit and cut it with a utility knife. Slide the new piece into the track. Staple it every three inches Cut off the excess and secure it with new nails.
Close the door and investigate the door frame. Some garage door frames have weatherstrip and some don't. Weatherstrip on the door frame makes a seal and allows the door to fit tighter. This prevents air from blowing in. If your weatherstrip needs to be replaced or if you need to add weatherstrip, do one section at a time. Remove the old strip. Use a flange-style weatherstrip. Start at the top. Measure the distance and cut a piece to fit across the top. Staple it in place. Do the two sides next. Open and close the door a few times to inspect the fit. Make adjustments if necessary and secure the weatherstrip with nails.