Im still not the most confident person in the world but I feel that setting myself goals and reaching them really makes me feel better about myself and more confident.
When I first met my boyfriend I was poor, a student, no job, couldnt drive, was overweight and unhealthy. With motivation and encouragement from him I completed my course and got a distinction , got a job I enjoyed (at the time!!), passed my driving test, got fit and healthy. So really I think achieving what you want(realistically) in life can do wonders for your self esteem.