As always said you must work from the botom to get to the top try to get into a good fashion school visit art galleries and museums for ideas and inspiration. try to get an internship or any sort of job at a fashion house ( even a secretary will do for the mean time)
create a portofolio put in all your best drawings and stuff you have designed and send it to a fashion house of your choice ( more than one if you want). Make sure you have a good knowledge of the history of fashion ..make sure you know how to sew and combine different materials and fabrics. Make sure your portofolio is neat and organized as proffesionials will be viewing and you DO NOT want to make a bad impression you must have passion,confidence,determination and believe it or not MANNERS!