I have been working with this Havanese puppy, Migo, on training him to go into his crate. I did this by making the crate a hugely valuable place to be (from his point of view), by using clicker training and positive reinforcement.
You can see how much he enjoys crate games by how fast he runs back in. Since he is moving in so fluidly, it was time to begin adding a cue just as he is on his way into the crate.