Measure from the stitches below the armpits on one side to another.
Measure straight across the underbust band from edge to edge.
Measure straight across the narrowest waist line from edge to edge.
Measure from where the shoulder seam meets the collar to the hem.
Measure the circumference over the fullest part of your bust.
Measure your waist at the thinnest place.
Measure the fullest part of your hips.