There are 5 key measurements to consider:
BUST
Wear the bra you will be wearing with the dress, and pull the tape across the fullest part of the bust.
WAIST
Bend to one side to find the crease, that's your natural waist. Pull tape across the narrowest part and keep tape slightly loose to allow for breathing room.
HIPS
Stand straight and pull tape across the widest part of the hips and rear.
HOLLOW TO HEM
Stand straight with bare feet together and measure from the center of the collarbone to the floor.
HEIGHT(BARE FOOT)
Stand straight with bare feet together and measure from the top of the head to the floor.
Grab some measuring tape, and check out our How to Measure for a Bridesmaid Dress for a quick tutorial.