You're about to
embark on a very
difficult task that you haven't
tried before, or tried and
failed? Then try this...
Think of the very worst think that could possibly happen when you do it. I don't mean simple bad consequences, but the really horrible and at the edge of believability type things.
Are you about to try adding a hard drive to your computer? Then imagine that when you're installing it into the machine you slip and accidentally drive a screw right into the lead wire in the power supply, electrocuting yourself and dying. Now, when you actually try it, should you mangle the new hard drive, or bust the seal on it, then it's a pleasant event because you're still alive and healthy with only a little wasted money. Could have been much worse, right?
Or before asking that cute guy out, think about how it could be right where his girlfriend you didn't know he had gets to see it all and goes beserk and does all sorts of horrible things to both you and him, and even poisons him in a manner that causes him to lose his grip on reality and he blames you for everything and he breaks into your house and kills you right before killing himself. Now even turning you down is a positive.