Replace your worries with thoughts about how things could go right. Worrying can make you manifest what you're trying to avoid. When worries happen, challenge them by questioning how likely they are to happen. Then, think about what has happened in the past when you worried. Next, consider how bad the worst-case scenario would be if your worried thoughts actually happened. You'll likely realize it's not that big of a deal in the long-run.
For example, let's say you're worried you'll embarrass yourself during a presentation. How likely is that to happen? Has it happened before? If you did mess up, would it really matter? Would you still think about it a year later? You'll likely recognize your worry isn't really a big deal.
It also helps to think about what your life might be like in 5 or 10 years. Will the thing you're worried about even matter then? Probably not. For example, you might worry about failing a test, but you likely won't even remember the test in 5 years. [more][Less]