Measure while wearing a bra. Take measuring tape under arms, across shoulder blades, and around the fullest part of your bust. Make sure you don't hold the tape too tight.

Just where the band of your bra sits, across the ribcage and beneath the bust.

Bend over to one side and find the natural indentation in your middle. This is your natural waist, generally this will be just above your bellybutton.

Just above your hip bones, where the line of low rise underwear would sit. If you have a fuller bottom, this isn't necessarily the fullest part, it might be just above.