Bust: Don't squish yourself--measure all the way around your bust and back right at your nipple line, and make sure the tape measure is not lower.  (I normally wear a bra for this measurement)

Chest: Measure under your breasts but as high up as you can go, keeping the tape measure parallel to this line when you reach it around your back.

Waist:  Measure wherever it is the smallest (if you have "no waist" go around yourself right at the navel line).

Hips: Measure at the very biggest part--even if that is so low that you are almost on the top of your thighs.

Midway:  Measure midway between the very biggest part of your hips and your waist.

Thighs:    Measure wherever they are the biggest.

Knees:    Measure right above the knee.

Calves:    Measure wherever they are the biggest.

Upper Arm: Measure wherever they are the biggest above your elbows.

Forearms: Measure wherever they are the biggest below your elbows.

Measuring Tips