I'll be the first to admit I have pretty poor self esteem. For me it all started in primary school where I was considered "pretty", I didn't see it. Everyone said I was pretty but because of my self image I couldn't see it. How did I get over it? I didnt, I will forever more be a work in progress. Some days are easier than others to see myself in a positive light. Every morning before my shower I look at myself in the full length mirror and name at least ten features or parts of myself that like. - it's easier some days than others, some days I can list off at least twenty features that I love or adore. Other days I am standing there for at least a half an hour before I end up saying something like my hair is looking good.
I'd suggest to start slowly. Start each morning with an affirmation "I am a fierce goddess and I will success at all my errands/ endeavours I attempt today." Or something similar also look at yourself in the mirror in the morning, really look at yourself. List at least one feature or part of yourself that you love. You'll feel silly in the beginning but I promise if you keep at it that you'll feel more natural as you keep doing this routine each morning.
I can notice the difference if I forgo either one of these steps for a few days, I feel more confident and happier within myself.