ONE GOOD WAY to crush your own pessimism is to look at the thoughts you have when you feel discouraged and find mistakes in those thoughts. That is, find ways in which your thoughts are mistaken. Maybe you've exaggerated something. Maybe you're thinking about something in black-or-white terms when there are actually many shades of gray you are overlooking. And so on.
I don't usually recommend simply trying to think positive thoughts. The research has shown it isn't as effective at changing your mood as finding mistakes in your discouraging thoughts. But reframing is different. You can read more about reframing in this article from The Happiness Project: A secret to happiness: re-frame something that’s making you unhappy.
Most of the thought-mistakes you make are factual errors. For example, "Nobody loves me." That's probably a factual error. But what if you think something like, "I'm such a loser." Is that a factual mistake? Maybe you don't really think you can say whether that's true or false. In cases like that, we have another way of judging the thought: Is it useful? And this is where reframing comes in. If you judge a thought as neither true or false, but you know it is definitely counterproductive, you can then look to see if you could look at it some other way.
In other words, let's say you are trying to talk someone into being a distributor for your business, and you flub it badly and the person turns down your offer. You failed. And then you think, "I'm such a loser."
You realize your conclusion is self-defeating. It makes you feel demoralized, which makes you not want to try again with some else and puts you in a grumpy mood anyway which doesn't really help in your persuasion attempts. It's self-defeating, but you can't really discount it as true or false. So you reframe it instead.
"I'm a loser" is one way to frame the situation. But are there other possible ways? You bet there are. For instance, "I am brave for putting myself into such a difficult learning experience." That's a different possible way to look at it. It's a reframe. You're looking at the same circumstances in a different frame.
And look at the consequences of that reframe. Rather than simply feeling like a loser, now you are proud of yourself for doing it and you're looking for what you can learn from what happened. That is a much more productive way of responding to the setback.
The basic technique is to dig up your thought-mistakes and clean them out of your head. But when you come across a demoralizing thought that you can't decide is true or false, try reframing it. You will get back in the game quicker and feeling better.