I'm going to give some things to look for, but none of these are definite giveaways. It is very unlikely you will be able to tell a barely used human made trail from a game trail.
Hikers like to be very obvious about the trails they make, and established trails are well worn. If a trail is very narrow, has undisturbed or barely disturbed ground cover, and is a bit overgrown, it's likely to be a game trail.
Look at the ground cover. If it looks identical to the surrounding ground, it's more likely a game trail. Look for upturned or heavily compressed leaves (relative to the surrounding ground cover) and footprints. These are signs of human use, although the leaf disturbances might also come from animal use. Animals will use human made trails, so hoofprints don't tell you much either way. If you are somewhere without leaves, just compare the ground surface to the surrounding area. The bigger the differences, the more likely it is to be a human trail.
Look at the vegetation up top. If you see broken branches, especially from waist to eye height, it might be human activity. If you don't see broken branches, but there are none to snag your clothes or poke you in the eye, it usually means a person removed them.
Look for litter. This is a sure sign of human use. Keep in mind that the trail might just lead to a party spot for locals.
Additionally, game trails that do look like human trails usually revert to typical game trails in a hundred feet or so at most. So if you start following it, then realize it's getting harder to follow, it's probably a game trail.