Rather than improving your self-esteem drastically overnight, you are more likely to find yourself gaining confidence bit by bit over a period of time.
Counselling and psychotherapy can help to change the negative thoughts and perceptions you have about yourself and develop goals to increase your confidence.
Outside of counselling, you can improve your self-esteem by:
Celebrating small achievements
Utilising positive affirmations
Forming relationships with positive and supportive people
Taking on new challenges
Eventually, these conscious decisions will become habits, and when coupled with professional psychotherapy, you will find that your self-esteem has improved over time.