You can do that on your own by saying negative things to yourself. You can either be your own best friend or your own worst enemy - the control is yours. Positive self-talk helps you to develop secure attitudes toward your performance and validates your capabilities. You need to learn to control your emotions or they will control you. Positive affirmation statements are short statements designed to enhance your self-image, help you achieve a positive mental attitude and increase confidence.
Effective affirmations are clear, realistic and in the present tense.
Changing your self-talk is going to play an enormous role in increasing your chance for successful performances on a more consistent basis. If you re able to control your thoughts, you can accomplish more than you were aware of - the task is a hard one, but more than worth the effort. It s important to use repetition with your affirmation statements. This will help embed them in your mind. You need to identify situations in which you tend to be negative.