Coloured Stickers
Coloured stickers placed on your client at strategic landmarks help you with quick assessment.
They allow you to assess many landmarks at once and you don’t have to go through the trouble of finding all those difficult landmarks a second or third time. They are much more user friendly than tacks (just kidding).
Make sure they are wedge shaped, the arrows point towards the landmarks and they are big enough to be seen form a couple of meters distance.
With a bit of practice you can place them strategically so you can see them from different angle, e.g. from both the front and the side.