In addition to the previous advice, keep in mind that a MOSFET is very easily damaged by ESD, (static electricity) Just picking a mosfet up w/o being properly grounded, will often cause the mosfet to fail.
I do alot of ESD testing at my work; most people have a substantial amount of static electricity built up on themselves at any given time. The threashold detection level of an ESD discharge is between 2000-4000 Volts for most people. Any discharge of static electricity, less than that, can't be normally felt. I think an ESD charge of between 50 and 200 volts can fry most mosfets.