Everyone knows that all gangsters are Italian and wear cheap black suits. All southerners talk with a slow molasses accent and chew on grass or spitting tobacco. All bimbos are blond. All surfers say "dude" a lot. All good guys wear white hats. Right?
Well, not necessarily so. When writing, its so easy to fall back on the same tired old stereotypes. Developing fresh characters is work--hard work. Main characters aren't so difficult. After all, we know our hero and heroine better than our secondary characters. But those others in the background require some thought if we want them to be more than cardboard cutouts.
Take the gangster stereotype as an example. A small amount of research would reveal that organized crime has spread to encompass all ethnic types and therefore all sorts of clothing. A gangster could be anything from Russian to Chinese to American. Clothing styles and distinctive marks such as tattoos are optional. Why not make that bad guy different?
Personally, I think that every single person has individual traits and interests that make them who they are. Why shouldn't our characters be the same? Why can't we have a man who not only chops wood, but does needlepoint in the evening? Or a woman who drives trucks for a living? Or an opera star who loves country music? How about a detective who loves police procedurals?
One of the easiest ways to make a character both distinctive and memorable is to "flesh out" their personal likes and dislikes in clothing--or to place them in a situation where they must dress against their personal preferences. For instance, every male from the outside who finds himself in Mystic Valley must deal with dressing in a kilt style garment. How each man makes those adjustments reveals something about who he is.
Personally, I think the most fascinating part of writing is to find out who the characters really are as the story unfolds.