You bring in only one size
Even if you’re convinced you’re one size, bring a size up and a size down with you to the dressing room. “Take the size you think you are, the size you wish you were, and the size you might be,” says Lauren Rothman, fashion stylist and author of Style Bible: What to Wear to Work. Different brands fit differently, so the best fit might surprise you. Don’t get discouraged if you do end up in that larger size. As long as you look good and feel good, the number on the tag doesn’t matter, says Rothman.
You rely on the fluorescent lights
Dressing rooms are often windowless spaces with fluorescent light—not the best for getting a true sense of how your outfit looks. “Look for close to daylight imitation rather than fluorescent light,” says Dina Scherer, wardrobe stylist and owner of Modnitsa Styling. “You’ll see the garment differently.” Pop out to the store’s main floor to get a better look at the outfit’s color, she suggests. If the store itself doesn’t have good lighting, make sure the store has a decent return policy in case the color looks off when you get home. Find out what your outfit color says about you.