This is a list. I thought I would create one for your enjoyment.
1) Check at your local bookstore. There is is usually a staff picks section. Powell's books
has a nice short Staff Picks section. http://www.powells.com/picks
2) Check at your local library. They usually have staff picks. This is a list of staff picks from New York Public Library. http://www.booksite.com/texis/scripts/bookletter/showlist.html?sid=5796&list=CNL3
3) If you use public transportation, watch for ads for books. I see ads for John Grisham on the New York subway as well as the Metro North.
4) Read the latest review material like Publishers Weekly or Kirkus Reviews. There are specialty review books like Horn Book for Children, Choice mostly for academic libraries, and VOYA-- Voice of Youth Advocates for teenage books.
5) Read popular magazines like Jet, People, or Newsweek. They all have book reviews.
6) Listen to the radio. Radio shows often talk about books. Jim Freund's Hour of the Wolf interviews science fiction authors. http://www.hourwolf.com/ . NPR-- National Public Radio often has authors reading.
7) Watch television. Most of the talk shows interview authors. Oprah Winfrey has a book club. It is one of those giant things. She revived a lot of classic literature. Charlie Rose invites quite a few authors. A lot of the documentaries on PBS are also in book form. Ken Burn's civil war series has an excellent corresponding book series.
8) Watch to see what other people are reading. People read everywhere, on the subway, at the park, in waiting rooms, and other places.
9) Attend readings if you can get to them. KGB Bar has a fantastic fiction reading series.
10) Watch the news. Every time something horrible happens, there is a new set of books coming out. O.J. Simpson spawned huge amount of books.
11) Check the obituaries. If an author dies, their estate often releases a lot of material for publication. Also, many people wait until after they are dead to have their biography released.
12) Go to book festivals. New York Is Book Country is the big festival of books for New York.
13) Go to conventions. Book Expo America is the giant book convention for the publishing industry in the United States.
14) Check out authors web sites. Neil Gaiman has an excellent blog. http://journal.neilgaiman.com/
15) Check out publishers web sites. Their new books will be featured prominently.
16) Make sure to look at your favorite cover artists site. I like Donato Giancola a lot.
http://www.donatoart.com/ They will describe the books which they are creating covers for.
17) Check the various writers professional associations. Most professional associations for writers give awards for quality new fiction. The Horror Writers Association has the Bram Stoker Award. http://www.horror.org/stokers.htm The Mystery Writers of America has the Edgars http://www.mysterywriters.org/
18) Check specialty genre sites like Science Fiction Site, or Uchronia, the alternate history list, http://www.sfsite.com/ http://www.uchronia.net/
19) Most genres will also have forums or newsgroups where they discuss a specific type of book.
20) Expect that your favorite writer in comic books might also write in other formats. Alan Moore wrote his autobiography, Peter David wrote both comic books and regular science fiction books.
21) Don't expect to see an author stick to just one genre. Joe Lansdale writes mysteries, horror, and westerns. Elizabeth Lowell writes science fiction, romance, mystery, and suspense. Walter Mosley writes novels, science fiction, and mysteries. Check to see if your favorite author writes in more genres than one.
22) Check the latest movies. Many of them came from novels. Read the novel before you go see the film. Richard Matheson's I Am Legend is just as good as the film.
23) You can find author readings on Youtube. This really surprised me. I put up a video of Jonathan Carroll reading from Youtube earlier on this site.
24) Philip Jose Farmer has a myspace.com page which is pretty interesting. Authors are taking advantage of the new media. http://www.myspace.com/pjfarmer
25) Authors also do podcasts. Bantam Dell has a nice list of podcasts by authors.
26) Don't forget to support your local library. Go to local library booksales put togther by the Friends of the Library.