You don't have to rely on just clothes to set your personal style. Try accessories, too. Some people are known by their signature hoop earrings, gold brooch or Chanel scarf. Think about certain celebrities and what you see them in: Uggs, Jimmy Choos, nameplate necklace, Birkin bag ... etc., etc. That particular piece becomes a part of her, part of her personal style.
Pick an accessory you love and run with it -- cocktail rings, bangle bracelets, scarves, flats -- something that people see and immediately think of you. Just don't make it too outrageous. The accessory you choose should be something you can wear just about every day -- bold enough to give your look a unique flair, but not so bizarre that it sticks out like a sore thumb.