"For anything you want to work harder for, you have to go beyond that threshold," he writes, "because you grow into a totally different, much stronger person."

5. Bribe (or punish) yourself

Not all routes to improved motivation are high-minded. One of the more effective ways will also motivate your dog--simple reward and punishment. "Make yourself an offer that you can't refuse," suggests analyst Deepak Singh (but don't go as far as Don Corleone, please).

Both positive and negative incentives can work. "For example, if you want to read a book, set a deadline and a reward. Say, if you love ice cream, you could eat some as soon as you finish the book," suggests Singh. It might not sound very grand, but pushing yourself to complete a task by dangling treats (or the threat of public humiliation or a pay-out on a bet with a friend) appears to be effective.

What's your top trick to get your motivation back up when you feel it sagging?