Pull the drawers out gently, and place them with the runners up on a table. Inspect the drawers for any sign of damage, such as loose or broken pieces. Hammer the sides gently into place if they are loose, and glue any broken pieces with wood glue.
Inspect the runners. If they seem rough, sand them lightly with fine sandpaper.
Apply a thin coat of paraffin wax, beeswax or liquid beeswax to the runners. These products lubricate the runners so the drawers will open smoothly, with no creaking or sticking.
Cut a piece of self-adhesive nylon tape to fit the length of the runners, for a more permanent solution. Pull the adhesive off the back of the tape, and place the nylon tape over the runner. Press the tape down firmly to secure it. Cut excess tape off the sides of the runners with a utility knife.
Insert the drawers back into the furniture, and slide them in and out a few times. They should slide smoothly, with no creaking or sticking. If not, repeat the processes.