BUST
Measure across the garment, 1" below the underarm seam and double the figure

WAIST
Measure across the garment, in-line with your natural waistline and double the figure

HIP
Measure across the garment, in-line with your hips and double the figure

THIGH
Measure across the garment, 1" below crotch point, parallel to leg opening and double the figure

INSEAM
Measure the garment, from the top of the inside leg down to the hem

LENGTH
For tops/dresses, measure center back down to the hem 
For bottoms, measure from natural waistline down to the hem
For knits, measure from the highest shoulder point down to the hem