Bust - To measure the bust, wrap the tape around the fullest part of your bust with your arms down. Keep a finger's gap.
Waist - To measure your waist wrap the tape around the slimmest part of your torso. To find the natural waist just bend sideways and the part that contracts is your waist.
Hip - Place the tape around the widest part of your hip which is usually 6-7 inches below your belly button.
Upper Arm - Measure the circumference of your arm's mid point. Make sure that the tape isn't too tig