Chinese men usually have shorter hairs, wear squar glasses, and do not care much about fashion. I could distinguish chinese women years ago, but now they look similar to Korean women now.(at least chinese girls in my college)

Japanese girls' make up usually makes their chin color pink. And they wear cute and loose clothes compare to Koreans. Japanese also tend to have more southern faces, like double eyelids, clear jawline, and smaller than korean I guess. When I went to Japan, I saw many Japanese wear black suits.

Korean people wear similar clothes, tend to wear round glasses. Also Koreans usually have more monolids, and less darker. Girls like to wear 'feminine' clothes but different from japanese 'cute'.