Today, create a side character (someone who will appear in a story but isn’t meant to be the main character). Base the overall image on a stereotype, but then give the person a quirk that’s completely unlike that stereotype.
When we last moved four years ago, we culled much of our book collection to make moving easier. We took a number of our books to a free book exchange at the local dump, and filled the shelves with roleplaying volumes, science fiction and fantasy, and even cookbooks. This was in New Hampshire, and on one of our trips back to drop off more books we spotted two men—one maybe in his 30s, the other in his 40s or 50s—who seemed to fit the New England redneck stereotype. They were dirty. Their hair was wild. They wore overalls, one of them without a shirt underneath.
And they were exclaiming with joy over the science fiction novels as they gathered them up by the handful.
It was completely unexpected, and I’ll probably never forget it as long as I live. That’s what makes a person real instead of a stereotype, and that’s what makes a character memorable and fascinating, even when he or she is just passing through your story or lending a bit of color to a setting.