I'm not an expert, but I'd say the best is to hope they notice you putting out food for them so they might start flying down to you when you come out with food, do it at around the same time of the day.
They are very similar but they are somewhat more inquisitive in examining their surroundings. They also share food with others especially if it's something they like.
Wan't to befriend a crow?
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.