Throw away from you and them, at about 90°. stand so arm movement is obstructed by your body. don't expect much first couple times. they'll get what you threw after you're gone and make a connection.
I used to sit out back and feed the squirrels, and a couple of blue jays learned what I was doing by observation. Although they never got as close as the squirrels (which were almost hand-tame within a few weeks), they did warm up quite a bit and didn't even freak out when their babies were hopping around right next to me. Maybe the same proxy method would work with crows if there are any willing squirrels in the neighborhood.
Haha, I always fed the local squirrels as a kid. I tried petting one once. The little bastard went into a chattering rage and chased me down the street. To the amusement of several neighbors.
