For bust size measure around your chest at the fullest point of your bra cup. Make sure to go under your arms, not around them!
Measure around the smallest part of your waistline with one finger between your body and the measuring tape.
Stand with your heels together, keeping tape straight and parallel to the floor. Measure around the fullest part of your hips.
Stand with your heels together, keeping tape straight and perpendicular to the floor. Measure from the high point of your shoulders down the length of your back.
Find a pair of pants that fit you well and measure from the crotch seam to the opening at the bottom of the pant leg. Round the number to the nearest 1/2" to get your inseam length.