Build up your self-esteem
Learn to filter what other people say about you into categories. Some people say things that we do not realize about ourselves and bringing it to our attention helps us to better ourselves. Then there is the mean and catty things that we just need to filter out.
Practice. And it helps if you really don't care.
don't respect their opinion or them
Just remember that even if you were perfect there would be someone that would criticize you. So, you might as well just do what is right for you as long as it is legal and you aren't hurting anyone else.
Just be grateful that's your biggest worry and you'll be fine