Search under the seat of the chair for a lever that adjusts the chair's height. Flip the lever to raise the chair slightly. Adjust as necessary before resetting the lever back to the neutral position.
Spin the chair in both directions, if there is no adjustable level. The chair may get higher when spun in one direction and shorter when spun in the other direction, much like a screw.
Remove the wheels from the chair. Some wheels twist off, while others are attached with screws. Place the chair on several phone books taped together with duct tape to make an elevated platform. Taking off the wheels prevents the chair from falling off the platform.