Measure around the fullest part of the bust. This measurement is taken above the band of your bra, and may not be the same as your bra size.
Measure the smallest part of the waist. The natural waist is below the rib cage and usually above the bellybutton. Do not take this measurement around the waistband of your clothing.
The hip measurement is taken at the widest part of the hips (around your bottom!). Do not take this measurement around the waistband of your clothing, or where your hands fall when you “put your hands on your hips.”