I’ve heard of writers getting trademarks for their books.  How does one do this and what has to be done?

Titles and characters as trademarks are possible but not personal names. Trademarks perform a different function than copyrights. First of all, understand the purpose of a trademark and why it is not for a single book even if the writer is productive. Protection of single works comes through copyright. A trademark is a source indicator. It presupposes the author is offering goods or services to consumers. Books produced and distributed by an established publisher (to take an easy example) is a good the publisher is offering in commerce. It is not the author who is offering the work but the publisher. A writer’s intellectual property is in her copyright. If, on the other hand, the writer has established a publishing company or another business for the purpose of self publishing and distributing her works (or offering merchandize based on those works) and her list includes more than one published work or she has a business that includes her writing she has a basis for a trademark, but not otherwise. Personal names as such are not registrable for trademark but character names would be if they recur in series.

A writer can get a trademark as a source indicator if she offers goods such as (but not limited to a variety of classes) downloadable files (Class 9) or printed matter (Class 16) or offering services (teaching the craft of writing) (Class 41). However, she cannot get a trademark on a single book or the title of a book.