Ask if you can try it on somewhere - if not, see if it can be exchanged. If you can do neither, it's not a good bet unless it's something like a cardigan or shoes which you can try right there. Pay in cash . Most places don't take credit cards or checks. Be prepared with cash and exact change.
Some stores have multiple levels.
Check upstairs, you might find what you like. Don't be afraid to ask if there's anything more. Broaden your style . Go for classics if you can, but be willing to try other stuff. Buy a neutral-colored one you can wear over black.