The optimum settings can vary between monitors, but usually you'll want saturation about in the middle. Sharpness can be calibrated using this site:
http://www.lagom.nl/lcd-test/sharpness.php
If you have or can buy a colorimeter or spectrophotometer, that's the best way to optimize brightness and contrast, though there are differing opinions on the optimum target brightness - TFT Central says 120 cd/m2, but Anandtech says 200 cd/m2. Otherwise, use the lagom site to calibrate your contrast, and experiment with the brightness to see what level looks best to you.