Make sure the clutch master cylinder is filled with the correct fluid (DOT 3 brake fluid). Loosen the bleeder screw at the slave cylinder. Push the clutch pedal down slowly until all air is expelled (bubbles in the fluid); do not release the pedal but hold it depressed. Retighten the bleeder screw. Release the clutch pedal. Refill the master cylinder to the correct level.
This process may need repetition several times; the key point to remember is that the clutch pedal MUST be held down until the bleeder screw is tightened. If the pedal is released with the bleeder open, air is sucked into the system.
Continue bleeding the system until no air is expelled with the fluid. When a steady stream of fluid is obtained, tighten the bleeder and top off the clutch fluid reservoir.