Getting a horse into a trailer?

I've just bought a horse and will be picking her up on Sunday. The woman who sold her to me (not the owner- the owner couldn't care less about the horse and let her be sold by the barn she's boarded at) said the horse has only been in a trailer once in her life (she's 6) and she anticipates difficulty getting her to load. What are some good non-confrontational ways to get a horse to load? Obviously if it takes all day to get her in, it takes all day, but I'd rather it took less time. I don't have my own trailer so a friend of a friend is helping me out and I'm sure she doesn't want it to take all day either. I don't know what kind of trailer she has. And unfortunately I don't have any time to work on this before Sunday with her. What would you suggest I try? thanks.