Here's an interesting excercise. List actors that you would cast in the following roles:
Sherlock Holmes:
Dr. John H. Watson:
Professor James Moriarty:
Irene Adler:
Inspector Lestrade:
Mycroft Holmes:
Mrs Hudson:
Colonel Sebastian Moran:
Inspector Tobias Gregson:
Inspector Stanley Hopkins:
Inspector Athenley Jones:
Charles Augustus Milverton: