Chest
Measure under your arms around the fullest part of your chest, keeping the tape parallel to the floor.

Waist
Measure around your natural waistline. Keep the tape comfortably loose.

Hips
With your feet together, measure around the fullest part of your hips.

Inseam
Lay a pair of pants that fit you well flat and measure the inside seam from crotch to hem.

It is best to have someone take the measurements for you, measuring over undergarments only.