Know your measurements, and re-measure every so often to allow for body fluctuations. If you want a garment to fit like a glove, look for measurements that are almost identical to your own measurements. For a comfortable fit, look for items with measurements a few inches larger than your own. For a loose or oversized fit, look for pieces with measurements that are much larger than your own measurements.
To find your measurements, take a tape measure and wrap around the circumference of each area of your body to find your measurement.
To find your bust measurement:
Wrap the tape measure around the largest part of your chest, which is usually right across your nipples.
To find your waist measurement:
Wrap the tape measure around the smallest part of your torso, usually an inch or two above your belly button.
To find your hip measurement:
Wrap the tape measure around the largest part of your hips, usually near your hip bones.
As a general rule of thumb for women’s vintage clothing, your size for clothing made before 1980 is double your current dress size. If you are a modern size 6-8, try a vintage size 12. If you are a size 10-12 today, try a vintage size 14/16, etc. Odd sizes (1,3,5,7,9, etc) in women’s clothing are usually made for petite women or juniors, although many styles can be worn by all body types. Look at the piece to see if the proportions would work for your body; this is usually easy to gauge with a quick glance.
If you love a piece but it doesn’t fit quite right, take it to a tailor for alterations. Tailors can let out a seam for more room, hem something to be shorter, take in a piece that is too large, and make other magical changes. Sometimes, all it takes is a few quick alterations to make a piece absolutely perfect for you.