Instructions
Get scanned. Thanks to advances in technology, it's now possible to get accurate measurements without even being touched by a measuring tape. Companies such as TC2 and Unique Solutions manufacture 3D body scanners that travel to various locations and scan your body without hassle for accurate measurements.
Consult a measurement chart specific to your country's sizes. A measurement chart can tell you what your approximate measurements should be, based on the size garment you typically wear. For example, a size 6 in the U. correlates to a rough measurement of 36 inches in the bust, 27 1/2 inches in the waist and 38 inches in the hips.
Consider the fabric. If you already have your measurements for a garment made in a stretchy fabric such as lycra, you can guesstimate the measurements for another garment in a fabric with less give by adding a few inches as required, or vice-versa.
Try on a garment for which you already have the measurements and take a visual inventory of the size discrepancies on your body (too loose in the waist by approximately 3 inches, too tight in the bust by approximately 4 inches).