What's the quickest way to learn how to hire an employee? TIA [DNO]

Hire 8 guys if he needed 4 for a job. Then he would sack half of them at lunchtime on the first day. Said it gave the others incentive to work hard.
However the world is a different place these days.
With all the hiring agencies, psychological testing and extended interviewing techniques, it is still hard to get the right person for the right job. If you are doing it yourself, after 20 or 40 interviews they all become a blurred mish mash anyway.
My own philosophy is to hire the first person I meet who appeals to my gut instinct, provided they check out, on a limited trial.
A lot depends on the job requirements and the business size. If this is a small business you need someone you get along with easily. In a larger firm proven abilities may be more important than getting along skills.