If you don't know the sender - don't open it! Booby-trapped attachments are often disguised in clever thank you notes or e-greetings.
Watch out for emails that request personal information. No legitimate organization will ask for your social security number.
Be careful with e-mails that look like they are from PayPal, Facebook, or other popular sites. Often these emails are linked to a third-party site that make them look official, but are actually run by thieves or scammers. Instead, just type the Web site's address directly into your browser.
Watch for typos or spelling mistakes. Scam artists are street smart, but many have flunked basic grammar. If the email has multiple typos or grammatical errors, odds are it's not real.
Watch for red-flag phrases, like "You have won!" or "Verify your account." Genuine firms never send e-mails like that.