First, you have to use the traditional tulip shaped British pint glass (about 20 oz). Hold the glass at a 45 degree angle to the tap and fill until the glass is about 2/3 full.
Next, let the Guinness settle for at least 3 minutes. Don’t forget about it though; nothing is worse than making a customer stare at their not-yet-served Guinness for too long.
Finally, top of the pint and let it settle once more before serving.
Guinness Master Brewer, Fergal Murray, suggests a perfect way to drink your pint as well. He says, one should sip from the same spot on the glass. Fergal aims for the Harp above the Guinness logo.