Decide on what type of fog machine is necessary. A consumer fog machine will best deliver the needs of an amateur user. The occasional Halloween party would only need a consumer fog machine. The high-speed fog machine will serve industrial users best. It is best for very intense and ongoing use.
Determine the wattage needed. Most consumer machines will have wattage between 400 and 1300 watts. High-speed machines will have wattage that is 1300 and higher. Higher wattage keep machines from going into reheat cycle, so the higher the wattage, the less the fog machine will have to work.
Look for the bells and whistles that come standard on the fog machine. Features like a timer remote control is a nice extra for a fog machine. The advertised cubic feet is also a feature that should be reviewed. This is not an exact science, so expect the fog machine to perform somewhere in the vicinity of the marketed surface area.
Perform an Internet search after all desired features have been determined. Knowing what to look for is half the battle with an item like a fog machine. Following Steps 1 through 3 will reveal the exact fog machine that is needed.