@briankrebs I've got one basic rule: When I receive a mail that could or could not be phishing, I visit their page, login and check from there. I recently got a message from Dropbox telling me that there are problems with my credit card - and it really looked phishy. Luckily after logging in there I saw the same message.
I really don't understand why companies often don't refer to their pages to validate the mail from there.