So you've made your way here- that means that you've seen how affordable a tux is to own.
But when you're in the Fitting Room, you must follow one of 2 rules of thumb...
1: Always have someone help you with fitting- a friend, a wife, anyone.
2: Have a professional tailor measure and write out a card for you, this way you know what you're getting.
Coat Size- This is the measurement you take of your chest at where your lungs are, just under your armpits.
Shirt Size- Neck:
To measure your sleeve length, from the middle of your neck measure along your shoulder and arm to the wrist.
Pant Size- Waist: Inseam:
To measure the inseam of your pants, take a nice pair of slacks and measure from the crotch to the bottom of your pantleg. To measure the outseam, use the same pair to measure from the waist to the bottom of your pantleg.