Above all else your Art -the ability to draw- and the Tattoo's you choose to place on your body (when your of age) will make you stand out
Do Not rush in-to getting Tattoo's wait until your old enough legally
and do your research
I've seen great people turned away because the tattoo's already on their body were so poorly done - it can turn customers away
Start By
Taking any and all of the art classes you can in school (AP especially)
they are free and all the materials are provided
AP- or advanced placement in art is offered at some schools as a high school senior
this course is ment to get a portfolio ready for art school
but in your case if you tell your teacher your dream of going on to be a Tattoo Artist
they will help guide you
outside of school go to local art stores (and professional artists) many offer art classes
take cartooning, still life, and portraiture <<-- This YOU SHOULD HIGHLY consider
ask your parents for art classes for your birthday or Christmas
these things will help you be able to understand proper blending of colors, how to shade, and how to draw images in front of you so that you can create personalized Tattoo's
and give you creativity
trust me ART is important!