How to calculate fair price of listed share..?

Dear Freinds and Professional i want to know that how to compute the fair value of the share in practise so i can compare this fair value with actual market price of the listed share which is hosted on nseindia.com etc. so i can take decison whether this share is overvalue or undervalue or indifrrent so i can take the decison to buy hold or sell the share..please suggest the best and practicle method to compute fair price of listed share..?? and Thanks in Advance..