1) credit card payment is all lower case and/or obvious non understanding of how US addresses are formatted
2) domain name has "hack" or some foreign sounding word. Or is anything related to vietnam (get plenty from vietnam)
3) IP location doesn't match customers location
4) Multiple attempts in a row with different credit cards
5) Registrant name doesn't match the name on the credit card and/or address
6) Customer name doesn't relate to email address used in any way.
Once again no one factor is definitive usually but a combination of several together almost always indicate a fraud order.
Those are off the top there are more. Bottom line is when you simply look visually at the orders you can tell with near 100% certainty that an order is fraudulent.
Otoh, here is a fictional example of an order that wouldn't appear fraudulent at all:
domain: bobspartycity.com
Registrant: Bob Wagner Address: 76 Walnut St., Williamette IL bobspartycity@gmail.com And IP is in that vicinity etc.
...etc. It could be of course but we've never had a case where a fraudster puts much effort into faking an order using knowledge of what we look for.