Tough question. It was asked by Dr Jessica Barker during the last (ISC)² Secure Summit in Amsterdam. There was hundred of security professionals in the room. The answers were quite classical at start: Passwords, phishing, trust, and so on.
The best suggestion, from my point of view, was this one: Ask for help!
Too often, users don’t ask for help. Likely because they don’t want to loose time waiting on the line while calling the helpdesk or they don’t want to look stupid (and there is probably a lot of other reasons and a mix of it). But security has become an increasingly complicated matter over the years. Hoping our end users will become better or as good as security professionnals might be a wishful thinking (although, in some cases, average users are better than most security professionals in some security specific tasks, I’ll come back to that another day).
So, « Ask for help », is the most reasonnable action to ask to our users. It is something they can easily understand, it will cover a large panel of situations and probably increase your reaction time and decrease the number of incidents.
Of course, you need to make it easy (simple phone number, easy to remember email address, one button to click in an email to signal a fishing attempt), responsive (people don’t like to wait) and nice (you don’t like that the person on the line make you feel like a fool).
Think about it. It might be a good start for a more human centric security (hence more efficient and cost effective).