Take your junior bridesmaid's measurements using a soft, flexible measuring tape.
CHEST:Measure around her back and under her arms to the fullest part of her chest.
WAIST:Have her stand up straight and bend to the side, creating a crease. Measure around the crease (the narrowest part of her natural waist).
HIPS: Have her stand with her feet together. Measure around the fullest part of her hips and seat.