Someone on a mailing list posted this link (thanks Lyn!) and I had to pass it on. Daniel Jose Older, an SFF writer and editor, wrote an article called 12 Fundamentals of Writing "The Other" (And The Self). If you write, or have considered writing, about characters who are different from you in some basic way, this'll give you some good stuff to think about.
I particularly like #5 -- "Racist writing is craft failure." Absolutely. It's easy to reach for obvious traits or characteristics without thinking about it, and have your hand fall onto a racist (sexist, homophobic, etc.) cliche. If bigoted cliches end up in your story, they're like any other cliches and make the writing weaker and more shallow.
Good stuff, check it out.