To take the most accurate measurements get a friend to assist. You will need a sewing measuring tape, or can make do with a piece of string that you measure against a hard measuring tape, as well as a note pad to keep track. For best accuracy take the measurements three times to ensure that the values are consistent.
What measurements to take:
Full Bust: measured around the fullest part of the bust (over the nipple) with bra on and parallel to the floor
Upper Bust: same as the Full Bust measurement, but above the bust
Under Bust: same as the Full Bust measurement, but underneath the bust
Waist: measure around the smallest part of your waist (normally just above the belly button)
Hips: measure over the largest part of your hips (the biggest part of your bum)
Shoulder to Shoulder: Measure from your one socket (where your sleeve on your shirt would normally start), across your back to the other shoulder socket (see picture)
Shoulder to bust: Measure in line with your nipple, from the where the top of the shoulder to the nipple
Shoulder to waist: Same as above but hold the tape measure on the nipple and measure to the waist
Nipple to nipple: Measure from one nipple to the other with your bra on
With Wedding Heels on:
Full length: (similar to shoulder to bust/waist measurement) measure from the top of your shoulder (in line with your nipple) to your nipple and then to the floor (about 1 cm above the floor or where you might like your hem to be)
Hollow to Hem: measure from the little hole in your chest where your neck meets your chest, down your front to the floor (about 1 cm above the floor or where you might like your hem to be)
Outer Leg: on the side of your body, measure from your waist, over your leg to the floor (about 1 cm above the floor or where you might like your hem to be)
Mermaid: Measure your outer leg, from your waist over your hip to the point on your thigh where you would like the mermaid/flare to begin.