Bust - Measure around Chest at the fullest point of the bust and under the arms
Natural Waist - Measure around your waist at the narrowest and add 1/2" for comfort
Hips - Stand with your feet slightly apart and measure the fullest part of your hips and add 1/2" for comfort
Inseam - This is from the center of your body at the crotch area to the desired length (i.e. ankle, floor, etc.)