Free e-mails are easy to setup than domain names/web sites. Any order from a free e-mail service must alert you (+1 fraud score).  Fraudsters will try to hide after a free e-mail service.

As I noted previously all orders are done from well know ips. If the ip maps to a proxy address, this is 100% fraud. If it does not map to a proxy server address, you can check

1. IPlocation country to billing address country
2. IPLocation city to billing address city
3. IPLocation provides some Latitude and Longitude value. You can calculate the distance to billing address. Any distance bigger than 1000 kms must warn you (+1 fraud score)
4. You can also check phone number against valid prefixes for IPLocation city/country and billing address
5. You must check zip code against city/country of billing and IPLocation address