Summarize the following:
Place a thin piece of paper between your refrigerator door jamb and the gasket. Pull the paper out from the refrigerator door. If the paper comes out easily without resistance, the problem with your door closing lies with the faulty gasket. Consult the manual for your refrigerator to determine its model. You can find the model type printed inside or on the cover of the manual. If you cannot determine the model of your refrigerator, contact the manufacturer directly by visiting their website or calling the phone number provided in the manual. You can also cut out a small piece of your gasket from the refrigerator door and match it to the gaskets in stock at a retail store that specializes in home repair or refrigerators. In the event your gasket needs to be special-ordered, reattach the gasket piece to the refrigerator using glue or rubber cement. A new gasket can be obtained directly from the manufacturer or from a retail store that sells refrigerators, appliances, or home repair supplies. The gasket must be of the correct temperature to seal and work properly on your refrigerator.  Consult with the gasket instructions if they are provided with the new gasket to determine the method of preparing it for use with your refrigerator. If no instructions are provided, leave the gasket in the same room as your refrigerator for at least 24 hours to allow the gasket to conform to the same humidity and temperature levels of the current gasket. You can also try soaking your gasket in warm water until it becomes pliable enough for the seal to work. The removal method may differ depending on the properties or materials that hold the gasket in place on your refrigerator.  Examine the gasket on your refrigerator to determine how it is held in place. The gasket may have adhesive strips, screws, or clips that fasten it to the refrigerator door panel. Use the appropriate tools or methods to remove the defective gasket. For example, if the gasket is held in place by screws, use a screwdriver to remove the screws. If adhesive strips are in place, use a putty knife to pry the gasket away from the refrigerator door panel. Pull the gasket away from the door panel one side at a time. This will allow you to verify that all fastening components have been completely removed, preventing pieces of the gasket from breaking off and being left on the door panel otherwise. This will allow you to remove any residue that has been left behind from the old gasket; such as adhesive or dirt that may present difficulty when applying the new gasket. Use a sponge with liquid dishwashing detergent and warm water to clean away remaining residue. You may use a steel wool scrubbing pad in place of the sponge to clean any stubborn residue that is difficult to remove. Depending on the manufacturer of the gasket and refrigerator, the tools needed to attach the gasket may vary. Refer to the instructions of your new gasket to determine which supplies are needed; such as screwdrivers, adhesive tape, or gasket cement. Apply the gasket to the door panel one side at a time; ensuring that each side is straight and aligned properly. Smooth down each side to ensure it lies flat against the door panel without any bumps, or curling edges. Use the tools and supplies indicated by the manufacturer to secure the gasket to the door panel; such as screws, bolts, clips, adhesive, or gasket cement. If you use gasket cement or adhesive glue to fasten the new gasket, you may need to allow the materials to dry before you can begin opening and closing your refrigerator door again.

Summary:
Verify that your refrigerator's gasket needs to be replaced. Determine the type of gasket needed for your refrigerator model. Purchase a new gasket. Prepare the new gasket for the refrigerator. Remove the defective gasket from the refrigerator. Clean the gasket mounting area on the refrigerator. Obtain the supplies needed to attach the new gasket. Attach the new gasket to the door panel.