Pull on the manual override cord that hangs down from the garage door's guide track. Pulling on the cord will open and close the door when the garage door mechanism fails.
Inspect the garage door mechanism, located in a box near the end of the guide track. Use a flat-tipped screwdriver to adjust the pressure settings to make it easier to open your garage door.
Place two tension rods along the back of an older, warped garage door, from the bottom left to the top right corners. Attach the rods together in the center with a thread coupling. Gradually tighten the coupling to straighten the door so it will open more easily.