Bust - Measure around your body under your arms and over the fullest part of your bust.
Waist - Measure around your body at your natural waistline. Keep the measuring tape comfortably loose.
Hips - Measure around the fullest part of your hips, placing the measuring tape below your belly button.
Inseam - Take a pair of pants that fit you well and lay them flat. Measure the distance along the inner seam.