As an adjective describing a person:
* She was a shy child who rarely spoke up in class.
* He felt shy around new people, but he was actually very friendly once you got to know him.
* The shy puppy hid behind its mother when we approached.
As an adjective describing a behavior:
* He gave a shy smile and looked away.
* The dog offered a shy lick to the stranger's hand.
* The artist's shy brushstrokes created a delicate and nuanced painting.
As an adverb:
* She spoke shyly, her voice barely audible.
* He smiled shyly and mumbled a hello.
* The cat approached the new toy shyly, sniffing it cautiously.
In idiomatic expressions:
* She was too shy to ask him for a dance.
* He felt a shy sense of hope that he might be chosen for the team.
* He gave her a shy wink, hoping she'd notice.
Remember, the way you use "shy" will depend on the context of your sentence and the message you want to convey.