While you might not be able to try the dress on before buying it, making sure you've measured your every area of your body and measured them again can help you get the best-case scenario when placing an order.
What's more, don’t just trust the labeled size on the dress, ask for specific measurements of the previous-owner – the dress may very well have been altered.
When was it worn? Has it only had one previous owner?
If you’re going to buy anything online, it’s always important to ensure that you’re purchasing from a credible seller – this is even more important when buying second hand.
Make sure the dress is stain-free before you buy it. Get a thorough description, a report if possible, and ask if the gown has been professionally dry-cleaned, how it has been stored.
Don't let stock photography trick you into feeling comfortable. Ask for a picture of a real person wearing the dress.
Search online for the brand and a similar dress to make sure you're getting a good deal.
Even if you’re buying a high-end designer gown from a reputable source, it’s still a good idea to ask to check the dress for a receipt or some other proof of purchase to make sure you’re getting what you paid for.
There's of course a chance you might not like the dress in person and different retailers have different policies regarding whether a dress can be returned. Make sure to confirm what the store's return policy is before you buy.