Avoid blatant stereotype characters, especially for the good guys or bad guys. This is especially advisable for those that carry a racist spin. Challenge your own prejudices and you’ll do the same for your readers. There are good guys and bad guys of all races, religions, nationalities, and so forth, so be fair. Furthermore, if you character has overcome the negativity associated with a particular group and thus invited the rejection and possibly the ire of his peers, you have some built-in conflict to work into your story.

I’m not saying that you should always be politically correct. Like Steve Jobs supposedly said, “If you never want to make anyone mad, then sell ice cream.” Some of the funniest books I’ve read have been quite politically incorrect, but they have done so under the guise of satire, which can get away with a lot of blatant rudeness. Satire is a very special case and not always easy to handle. More on that some other time.