The neck measurement is taken around the neck. You should put one finger between the tape and the neck to allow for some extra room.
The chest measurement is taken as a circumference measurement around your chest at the widest point with one finger between the tape and the chest. Stand in a relaxed posture and breathe out.
The waist measurement is taken as a circumference measurement around your waist just above your belly button with one finger between the tape and the waist. Stand in a relaxed posture and breathe out.
The Hip measurement is taken as a circumference measurement around your seat at the widest part with one finger between the tape and the hip.
The shirt length measurement is taken from the center back, just under the collar till the point you want your shirt to end. Stand in an upright position while taking this measurement. Typically, the shirt should end just under the hips.
Think of a line going from your armpit straight upwards to your shoulder. Measure between those two points and hold the tape measure straight.
The sleeve length measurement is taken from the point of your shoulder (where you took the shoulder width measurement), following your straight arm down to the point where your thumb starts
NOTE 1! Keep your arm straight when taking this measurement.
NOTE 2! This measurement is always the full length of the arm.
Measure from the top of the shoulder, down the front of the shoulder, under the armpit and back up around to the top of the shoulder.
The biceps measurement is taken as a circumference measurement around your biceps with one finger between the tape and the bicep. Relax the muscle and measure at the widest part of your upper arm.
The wrist measurement is taken as a circumference measurement around your wrist with one finger between the tape and the wrist.