The Merriman Webster Online Dictionary defines the word "shtick" as follows:
1. an usually comic or repetitious performance or routine : bit
2. one's special trait, interest, or activity : bag <he's alive and well and now doing his shtick out in Hollywood — Robert Daley>
It is a common practice for fiction writers to give a character a shtick in order to make it easy for the reader to visualize him and to distinguish him from the other characters. Charles Dickens did this with many of his characters. For example, in David Copperfield his character Mr. Micawber was always saying that something may turn up, while his wife is always saying something like, "I shall never desert Mr. Micawber." In that same novel David's eccentric aunt Betsy Trotwood is always throwing fits when people try to ride donkeys across her property. Uriah Heap is remembered because he is always telling people how humble he is and how he believes in being humble. Aunt Betsy's good friend Mr. Dick has a most unusual shtick. He can't keep from thinking about King Charles' head.
Aunt Betsey claims that Mr. Dick, an eccentric man who lives with her, is a “distant connexion” or relative of hers. Mr. Dick’s “vacant manner, his submission to [his] aunt, and his childish delight when she praised him” causes David to “suspect him of being a little mad.” David also sees evidence of mental problems in the fact that as Mr. Dick works on his autobiography he has difficulty keeping King Charles I from creeping into it. --eNotes Study Guide, "Characters."
In Great Expectations, Pip's sister is always complaining about how she had to bring him up by hand, and Joe Gargary frequently says, "What larks!"
Mr. Smallweed in Bleak House has a really unusual shtick. He is always saying:
"Shake me up, Judy! Shake me up!
It is never made clear exactly what is wrong with him, but he obviously has a serious condition such as rheumatoid arthritis or osteoarthritis which makes it impossible for him to walk. He has to be carried around on a litter, and he is always requiring this comical "shaking up." Naturally his affliction doesn't do anything to improve his temper. His daughter has taken on his own vile personality.
The word "shtick," which is Yiddish, is an extremely valuable word for discussing characters in fiction or in motion pictures. There are many other great Yiddish words, including schlemiel, schlep, schlepper, schlock, schmaltz, schnook, schmoe, and schmuck, all of which can be found in a good collegiate dictionary.
Charlie Chaplin entire "Little Tramp" persona was a shtick. He wore a derby hat, carried a little cane, had baggy pants and oversize shoes in which he walked like a duck with his feet turned out at extreme angles. The best example anyone could give of a shtick would be the great Charlie Chaplin because everyone has seen him. At the height of his career he was said to be the most famous man in the world.
Holden Caulfield's red hunting cap in The Catcher in the Rye was more of a shtick than a symbol of anything in particular.
Thanks so much, Bill!
Thanks for your acknowledgment. Glad my answer helped.