Want to be happy? Don't try to think yourself happy, just smile instead (regardless of how you feel). Want to boost your will power? Tense up.
Countless self-help books advocate that you think yourself rich/thin/happy, but that won't work according to author Richard Wiseman. Instead of positive thinking, he said in his new book Rip It Up, the best thing is to do positive action, as he explained in this article in The Guardian:
This is the granddaddy of them all. As Laird's study demonstrated, smile and you will feel happier. To get the most out of this exercise, make the smile as wide as possible, extend your eyebrow muscles slightly upward, and hold the resulting expression for about 20 seconds.
WILLPOWER: Tense up
As Hung's experiments show, tensing your muscles boosts your willpower. Next time you feel the need to avoid that cigarette or cream cake, make a fist, contract your biceps, press your thumb and first finger together, or grip a pen in your hand.
DIETING: Use your non-dominant hand
When you eat with your non-dominant hand you are acting as if you are carrying out an unusual behaviour. Because of that you place more attention on your action, do not simply consume food without thinking about it, and so eat less.
PROCRASTINATION: Make a start
To overcome procrastination, act as if you are interested in what it is that you have to do. Spend just a few minutes carrying out the first part of whatever it is you are avoiding, and suddenly you will feel a strong need to complete the task.