Take voice lessons. You want to learn how to bring out the best in your voice. Hiring a vocal coach can help you reach your greatest potential. Vocal coaches can remedy poor technique while addressing your strong and weak areas as a singer.
With a voice coach, you can practice increasing your range as well as experimenting with your vocal dexterity in front of someone who can offer valuable feedback. This practice and guidance will ultimately help build up your confidence in your singing abilities.