When you dig the hole, rough up the sides of the hole so that you're not planting in a "container" with slick sides.
Some experts advise digging a hole just a little bigger than the rootball, and putting no amendments in the hole, so that the hole does not become a container with looser, richer soil. You want the roots to grow beyond the hole, rather than reaching the native soil at the edge of the hole and then "deciding" not to venture beyond the nice, rich, cozy, amended soil. But I'd always add compost on top.
When I was taking hort classes, it was pointed out that the "how to plant a tree" instructions changed every few years. So one way to tell when the nursery owner started in the business was to look at the vintage of the tree-planting guidelines. As far as I know, the latest advice is what I said in the previous paragraph. But all I know is California planting. I assume your ag extension will have the latest advice, but then again, I've heard of one state's ag extension that still recommends adding calcium for BER, so... (Oh, and an alternative explanation is that if a nursery owner started doing it one way and has been successful, and new research says do it a different way, they may see no need to change.)
I think the "prune on top to match smaller root mass" advice that mensplace mentions has also been superseded.
Re staking, the current advice is to leave a stake for no more than 6 months. The ties should be loose enough so that the trunk can move a little. You want the tree to develop a good taper (thickness of trunk), just like tomato seedlings, by being buffeted gently back and forth by the wind. As soon as the tree is firmly rooted, the stake should be removed.
Anyway, here's a good source to follow up on horticultural practices and myths.
http://www.puyallup.wsu.edu/~linda%2...20myths_files/