Be sure to have lots of it. This is particularly true for Tomobiki-cho, the Nerima ward, Macross Island, old Buddhist shrines, most of Tokyo, esp. Shinjuku and other famous areas. Just throw out any science textbooks you have. None of it's going to work normally anyhow.
People tend to come in various personality types, body types and hair colors.
Unless of course the person in question is bleeding through the nose in which case you may want to make a discrete check of your clothing. Many people tend to have a nasty tendency to carry grudges to the grave. And they'll come back yearly just to do the Meposian Dance of Joy on it. Particularly when dealing with mysterious old strangers who sell you old and wondrous magical items. If there's a profound lack of them, you may wish to consider moving.