Check the spelling.
This is what I look for first. Scammers can't spell, probably because English isn't their first language.
Who signed it?
If it's a legitimate e-mail from a business, it will be signed with a person's name and contact information, but if it signs off with something vague, such as "Customer Support," be wary.
Does the e-mail scream at you in all caps?
Be especially aware of e-mails that try to get your attention by using all capital letters, especially in the subject line. Also, look for an excess of exclamation points and dire warnings, such as "Urgent!" or "Danger!"
The e-mail has an executable attachment .
Don't click on it even if it's from someone you know. A favorite way to send a scam e-mail is by making it look as if it were sent to you by someone in your e-mail address book, don't be fooled by the sender's name. Never download an attachment unless you are sure it's legitimate. Just clicking on it can install malicious software on your system.
The e-mail has a link to a web site
Don't click on that link. It might try to install software on your computer. It might also ask for your name, bank account number and online banking password to get onto the site. Don't ever provide this information if you got on the site by clicking a link in an e-mail.