Formal:
* The hotel's ritzy lobby was decorated with marble and gold accents.
* She wore a ritzy gown to the gala, complete with a diamond necklace.
Informal:
* We decided to skip the ritzy restaurant and grab some pizza instead.
* I'm not sure I can afford to live in such a ritzy neighborhood.
* He drives a ritzy sports car, but he's actually quite humble.
Figurative:
* He put on his ritziest smile and went into the meeting.
* The event was a ritzy affair, with champagne and caviar on the menu.
Remember that "ritzy" has a slightly negative connotation, implying that something is pretentious or excessively luxurious.