General:
* Copy
* Reproduce
* Mimic
* Emulate
* Replicate
* Follow
* Model
* Simulate
* Parody (often used humorously)
More formal:
* Aping
* Counterfeit
* Mock
* Feign
More specific:
* Echo (for sound)
* Mirror (for reflection)
* Emulate (to try to equal or surpass)
* Mock (to imitate in a way that is meant to be funny or disrespectful)
* Parody (to imitate in a humorous or satirical way)
The best word to use depends on the context of your writing.