Assuming you mean high-end (as in Vogue covers and such), then it's very simple. Learn the craft inside and out. Know lighting inside and out, every aspect of exposure and camera operation, and how to pose and light people and the clothing they're wearing to maximum advantage. Then, build a portfolio... an OUTSTANDING portfolio. Now, write out a resume and with your portfolio in hand, haul your butt around to the different fashion houses and high-end independant photographers... if you're very, very, very VERY lucky one of them will like what youve done and take you on as an intern. For the next few years you will carry equipment, fetch coffee and say, "Yes sir/ma'am" a lot. You will likely become well acquainted with the thin end of a broom and similar tools. On occasion, you may actually see a camera. Gradually (as in years) you MAY be allowed to assist by mounting lenses, checking memory cards & batteries, and eventually you may graduate to the person who actually hands the photographer his/her cameras.
It is now probably close to ten years later, and maybe, just maybe you will be allowed to start shooting some minor assignments. Filler, backgrounds, etc. Over time (another ten years) you may actually graduate to being the "the" photographer.
Good luck!