Measure over the FULLEST part of your bust. Be sure the measuring tape is level all the way around. (This will typically be a different number than your bra size because those numericals refer to the underbust, not full bust measurement.)

Measure about an inch or two above the top of your hip bones, where your waist perhaps creases when you bend a bit sideways. Keep the measuring tape level all the way around.

Place the tape around the widest part of your hips/buns. We're looking for the low hips here. (NOT the high hip, where the hip bones are). Be sure that measuring tape is level all the way around.

Place and hold the start of the measuring tape at your shoulder, then pass the tape between your legs and back up to the same shoulder (as if stepping through a loop). Be sure to stand up straight.