A schtick is a person's special way of doing things that makes them different or funny.
Schtick can make people think of comedy, jokes, or a person's special way of being.
Examples:
His schtick is telling jokes about cats.
She has a funny schtick about dancing with a mop.
The clown's schtick is falling down a lot.
My schtick is making silly faces.
The comedian's schtick is pretending to be a robot.
The magician's schtick is pulling things out of his hat.