It's a fact that the more you describe a person the more you hamper the reader to create his own picture.
That could be good or not (great help, isn't it?).
Ask yourself the question: how important is the look of the character for the story? What characteristic traits shall the person have?

If you want to underline his/her evilness, give him/her a scar across the face (I know it's an primitive example, but you get the point).

In my very own opinion it's the best to reduce, do compress the character's description to two or three very sharp, very clear distinguishing marks. Use them as a kind of "trademarks".

They could be exceptional long hair, scandinavic features, high cheekbones or even accessories like a pair of sunglasses.

To come to an conclusion: as many details as necessary, as few as possible.