Measure from the tip of one shoulder to the other, across the top of your spine and at the base of the neck. The tape should follow your back’s natural curve.
Maybe it will help you if you find an old blazer on which you should measure
CHEST / BUST
Stand normally and comfortably and put a tape measure at the broadest part of your chest, inline with the nipples, leaving enough room to breath.
Measure from the base of the neck at the shoulder seam to the nipple.
Measure around the narrowest part of the waits. It helps to bend side to side to identify exactly where to measure.Slide a finger between the tape and your body to allow some room.
Measure around the fullest part of your hips. As always – measure snug, but not uncomfortably tight. Leave a room for one finger, holding the tape.
Identify the largest part of your hips or butt, whichever spot above the thighs is the largest. Wrap the tape measure around your widest area. The tape measure should be loose for one finger so that you do not see compression of the skin.