That's a tough question to answer. I immediately think, "suit and heels," though I haven't dressed like that in years. Still, I think wearing a nice, well-fitting, dark suit and pumps made me feel very authoritative. It's a kind of uniform, and when I was in the Army, I think I felt quite powerful in many of my uniforms. Now I don't know that I dress in a way that makes me feel powerful, although I think wearing a Little Black Dress of some type, and again, a nice pair of pumps, makes me feel that way. It's that idea of the uniform again, the kind that signals a certain amount of experience and authority. This idea is in keeping with Rachylou's answer, too, isn't it?