it may be counterintuitive, but for skinny ties I tend to go with a slightly larger knot, so the knot is substantial enough to fill the space between the collar points. conversely, wider ties can handle a simpler, smaller knot, so the knot isn't too big relative to your face.
ties that are made of thicker material, like wool or old polyester ties, tend to look best with a small knot, i think -- if you try for a larger knot it might look more like a weird knobby lump than a proper knot
― elmo argonaut, Tuesday, 1 November 2011 21:49 (twelve years ago) link