I have shaved a fair number of people and what has been mentioned is great advice. While shaving someone else may seem simpler in one way it is more difficult in others. I have found that confidence is the key.
Take your time, watch the skin that it doesn't deviate from blade pressure, lots of lubrication, neutral balm and did I mention take your time?

Oh, the barber's chairs definitely make things nice, especially when you have access to an electric/hydraulic chair.