Firstly write down a statement outlining your intent and alter it so that it becomes an affirmation or set of affirmations. Make it present tense and very positive in nature. "I am increasing my confidence everyday", "I am self assured and self confident in every situation" and "I can feel my self-esteem increasing everyday" are a few good examples.
Ensure that you do not include the negative aspect your goal or what you do not want such as "I am no longer lacking in confidence" or "My low self-esteem is getting better". These statements focus on the situation as it is not how you want it to be. So remember keep the statement positive and only include what you do want! While still in a waking state imagine how you would look and feel if these statements were true. take some time now and create a mental movie of how you think the 'new' confident you would walk and hear their self assured talk and see how they interact with people. Imagine what kind of emotions this person would be feeling. Construct a movie in your mind that shows you as the confident person you wish to be. See yourself being that confident in circumstances that usually make you feel insecure, fearful or self-conscious. You will use this mental movie during your self-hypnotic trance session.