I agree with above. Short, neatly trimmed nails. You could have some pale or neutral conservative color of polish but this is optional. I would avoid long nails or anything bright, unusual, etc. You aren't going to be able to palpate properly when you start seeing patients with long nails and, indeed, hospitals have policies on nail length. I know you aren't a med student yet, but think it does show some insight to appear as physician-like as possible.