Shoulders
Shoulder width should be taken from one end of the shoulder to the other.

Chest turn
You need to wrap the tape measure around the widest part of the chest, running it under the armpits.

Waist turn
One must wrap the tape measure around the narrowest part of the waist.

Sleeve lenght
This measurement is to be taken from the end of the shoulder (you can take the shoulder frame as a reference point) by running the tape measure behind the elbow to the thumb notch.