Have a consistent place, bonus points if it has shiny bits on it. I had the best success when I put out stuff on a shiny tea tray.

They love peanuts, but if it's in shell peanuts the neighbors might start to complain. They also really like meat.

Try to create a pattern when you feed them. That way they learn to anticipate and rely on you. I have a distinct "feeding the crows" whistle.

I've only gotten gifts on very rare occasions. They left a toy soldier on the feeding tray. But they also will "play" with you. The crows at my old place used to steal my puppies toys and drop them on us when we were out for walks.