As a general rule crows are wild animals so don't try capturing them, let them fly free. If a crow wants to come near you let it be its decision, don't try chasing after them. If you find a wounded crow find a wildlife rehabilitator or contact a veterinarian.
If you rent a place or live somewhere temporarily (about 3 years) don't befriend them, they can live up to 17 years. Go to a park at the same time every day so that you and the crows form a routine and a relationship.
A good thing to feed them is natural nuts in a shell, it prevents the smaller birds from being interested but the crows are intelligent enough to break trough the shell to be interested. A good time to feed them is the morning or afternoon, when they are on the lookout for food.
Samurai champloo
Moomin