As most of the Girls have said Black or Nude never fail.
For me a little something I figured out is you don’t want your legs darker than your shoes.
To make an obvious example, if you have say white heels, go white or nude depending upon your outfit. Don’t use black.
Or lets say you have black heels, black, off-black(grey) or nude depending upon your outfit.
Its a judgement call depending on the situation. Nude never really fails, and black pretty much the same.