When you are positive and have positive thoughts, you attract positive things and positive experiences. This is just science and the basic law of attraction. Like attracts like. I'm not trying to convince of you of anything, it's fact. Your thoughts are electromagnetic waves, essentially energy that affect your mind, brain and body. And these thoughts attract similar circumstances or experiences. Therefore, if your mind is having negative thoughts then it's going to react by having negative feelings, and then you're going to have negative experiences and a negative outlook on what is happening or could happen to you. On the other hand if you have thoughts of contentment, openness and happiness, your body is going to react by having those feelings and it will attract those types of experiences.
When people are left in this world without this knowledge, without the ability and power to be in control of the experiences they have and their destiny, they resort to dealing with what gets dealt to them, as if their whole life is on shuffle mode, but all along they've had the ability to pick and choose which song they want to hear.
Now that I've told you that you're in control, you probably want some tips for when you feel like you're not... and I have that too.
First off, if you're nervous, scared or hesitant about anything, you probably need some confidence. A good way to get an instant boost of confidence is to strike power poses. There are lots of different ones to choose from, but essentially any stance or sit that opens you up and relaxes you out. Stand like Superman with your hands on your hips, elbows sticking out and feet set wide apart. Breath in and out for about two minutes in each and every pose, and feel the anxiety leave you as you breath in new positivity, and emanate it outwards.
And my second tip is to think positive thoughts! Even if it's the craziest thing to do and you're 110% sure it's not going to work out. Even if it's fake and you're just trying to make yourself laugh. Sometimes, just sometimes, things work out and good things happen, because for a split-second you decided to change your mentality and decided that you're in control. Decide to have a good experience.