I read Neduro's tire changing thread from beginning to end, before attempting my first tire change last Spring:
I have done several since, and while not fast, and not easy, no issues so far.
The best advice I found so far is:
1) if it gets really
hard, stop before you break something, because you're doing something wrong, so back off, and start again.
2) putting a little air in the tube helps keep it where it belongs, and away from the tire iron.
3) keep the tire in the deep, center of the rim