When planting large plants, like trees or large shrubs, I've always dug a hole larger than the root ball, filled it with water, and then suspended the root ball in the water and used my hand to separate the roots as much as I could. I always thought that this encouraged the roots to push into the surrounding soil and get a good hold rather than the roots circling round and round the ball formed when the plant was in the pot.
Are there other tips on how to ensure the survival of plants when they are being planted or transplanted?