If they contact you and don't have correct spelling, punctuation, grammar - yet have a Masters or Bachelors degree, don't bother.
Pay attn to details in their profile description and see if the picture matches - many times that will send up the red flag.
If they do happen to have a picture in their profile, you can right click it and search for the image on Google.
This almost always results in being some super model's images, and not the person in the profile.
The scammers provide you with a telephone number that does not match the geographical location that they list on their profiles.