Determine your unique qualities.
Invite some friends to help—possibly your partner, your superior, a professor—some intelligent people who will give you their honest opinions.
Use positive and cheerful phrases more often.
Everything has a good side. When you could not achieve something, instead of saying, “I tried it and failed.”, you can say, “I failed, but I will learn from my mistakes and try again.”
Focus on the important things.
Before becoming excited and sad over small things, ask yourself, “Does it contribute anything to what I aim to do?”