Focus on your positives.
People with low self-confidence tend to compare themselves to unrealistic idealizations of others, and thereby find themselves always coming up short. Instead of holding yourself to impossible standards and focusing on your failures, work on training yourself to emphasize your successes. Focus on why you deserve to have authority.
- Keep an updated list of personal accomplishments and positive attributes if that helps. Take note of compliments and positive feedback from others (and take them seriously). Surround yourself with positive reinforcement.