I try to find a style that matches the book. In the Baroque Cycle, I got infected with the prose style of the late 17th and early 18th centuries, which is my favorite era. It's recent enough that it is easy to read - easier than Elizabethan English - but it's pre-Victorian and so doesn't have the pomposity that is often a problem with 19th-century English prose. It is earthy and direct and frequently hilarious.
Neal Stephenson