Give crows a reward, and they'll remember your face/clothing
Scare them away, and they'll also remember your face/clothing
If anyone hypothetically wanted to, they could buy lots of dry cat food (which crows love), and teach them to like you
And you could also try to trample them/shoo them off, wearing CERTAIN UNIFORMS, teaching them to hate people who wear said uniforms
Thought this said cows, and got excited for a moment. Pretty sure people have been training crows for a while now. Remember the guy on 4chan who accidentally trained some corvids (can't remember if crows or not) to bring him change, and he was asking if it legally counted as stealing?