"Sign" is the word used by Guides to mean any little details, such as footprints, broken twigs, trampled grass, scraps of food, old matches, etc.
Some native Indian trackers were following up the footprints of a panther that had killed and carried off a young kid. He had crossed a wide bare slab which, of rock, of course, gave no mark of his soft feet. The tracker went at once to the far side of the rock where it came to a sharp edge; he wetted his finger, and just passed it along the edge till he found a few kid’s hairs sticking to it. This showed him where the panther had passed down off the rock, dragging the kid with him. Those few hairs were what Guides call "signs."
This tracker also found bears by noticing small "signs." On one occasion he noticed a fresh scratch in the bark of a tree, evidently made by a bear’s claw, and on the other he found a single black hair sticking to the bark of a tree, which told him that a bear had rubbed against it.
Details in the Country.—If you are in the country, you should notice landmarks—that is, objects which help you to find your way to prevent your getting lost—such as distant hills and church towers; and nearer objects, such as peculiar buildings, trees, gates, rocks, etc.
And remember in noticing such landmarks that you may want to use your knowledge of them some day for telling some one else how to find his way, so you must notice them pretty closely so as to be able to describe them unmistakably and in their proper order. You must notice and remember every by-road and foot-path.
Remembrance of these things will help you to find your way by night or in fog when other people are losing themselves.
These are the tracks of two birds on the ground. One that lives generally on the ground, the other in bushes and trees. Which track belongs to which bird?
Using your Eyes.—Let nothing be too small for your notice—a button, a match, a hair, a cigar ash, a feather, or a leaf might be of great importance, even a fingerprint which is almost invisible to the naked eye has often been the means of detecting a crime.
With a little practice in observation you can tell pretty accurately a man’s character from his dress.
How would you recognize that a gentleman was fond of fishing. If you see his left cuff with little tufts of cloth sticking up, you may be sure he fishes. When he takes his flies off the line he will either stick them into his cap to dry, or hook them into his sleeve. When dry he pulls them out, which often tears a thread or two of the cloth.
Remember how "Sherlock Holmes" met a stranger, and noticed that he was looking fairly well-to-do, in new clothes with a mourning band on his sleeve, with a soldiery bearing and a sailor’s way of walking, sunburns, with tattoo marks on his hands, and he was carrying some children’s toys in his hands. What would you have supposed that man to be. Well, Sherlock Holmes guessed correctly that he had lately retired from the Royal Marines as a sergeant, that his wife had died, and that he had some small children at home.