Make a list of the exact clothing items you want to purchase before you leave home. If you need to match or coordinate with other wardrobe items, take your wardrobe item with you to the store. Try on the item before purchasing to make sure it fits properly. You may not find the correct size if you have to bring it back for an exchange. Be sure you ask about and understand the store's exchange policy.
Some clothing stores have a time limit on returns.
Put the sales slip in a secure location immediately after you arrive home. If you find the item must be returned, you have what you need to make the transaction.