gm techniques – How do I roleplay Prejudice/Xism?

The world is not always nice place, and typically neither are our pretend ones. There are plenty of times in games where Characters may come across others who are prejudiced in some form. Perhaps mechanically, with Shadowrun’s Prejudiced Disadvantage, traditionally, like how Elves and Dwarves tend to dislike each other, or how all Tieflings seem to get disliked on principle.

Now, I’m lucky enough to have a fairly privileged upbringing, so I’ve not had to live through much, if any, prejudice. This does however mean I don’t know how to properly roleplay it, either as with a single character or as a GM showing entrenched prejudive in a society.

Obviously, I would need to make sure anyone I’m plying with is willing to deal with Prejudice before I put it in my game, but I believe defeating it would give them much the same satisfaction as saving the puppy orphanage from destruction, so it’s something I want to include. How then, as a GM, would I present subtle/overt prejudice from individuals or a society in a believable way?