A title can be a popular expression. Gone for Good, Something’s Gotta Give, The Horse’s Mouth, The Usual Suspects, Good As Gold, The Whole Nine Yards.
A title can be a play on words. (Sometimes a “twist” of an existing expression.) Burglars Can Be Choosers, The Cancelled Czech, You Only Live Twice, Live and Let Die, The War Between the Tates, A Hearse of a Different Color.
A title can have a hidden meaning, later revealed in the story. The Green Mile, Rain Man, Dances with Wolves, Catch-22, Hearts in Atlantis, Cool Hand Luke, The Shipping News.
A title can come from an existing work. (The Bible, Shakespeare, etc.) The Grapes of Wrath, The Sound and the Fury, The Sun Also Rises, Absalom, Absalom, All That Glitters, Something Wicked This Way Comes.
A title can be a person’s name. Hannibal, Goldfinger, Carrie, Hondo, Rebecca, Doctor Zhivago, Shane, Forrest Gump.
A title can be a place name. Cold Mountain, Cimarron, Peyton Place, Jurassic Park, Lonesome Dove, Mystic River.
A title can be a possessive. Portnoy’s Complaint, Angela’s Ashes, The Optimist’s Daughter, Charlotte’s Web.
A title can be an association of ideas. Often these are words that have a “double meaning,” and refer to more than one thing in a story. The Eye of the Needle, The Dead Zone, Misery, Silver Bullet, Lie Down with Lions.
A title can be an “event” or “activity.” (Use “ing” in the first word.) Pleading Guilty, Romancing the Stone, Waiting to Exhale, “Riding the Bullet,” Raising Helen, Finding Nemo.
A title can be a memorable line from the story itself. To Kill a Mockingbird, Tell No One, Sleepless in Seattle, The Eagle Has Landed, They Shoot Horses, Don’t They?
A title (if long) can have a “rhythm.” Another kind of “play on words,” this makes a longer title more pleasing to the ear–and easier to remember. The Spy Who Came In from the Cold, The Sins of Rachel Cade, At Play in the Fields of the Lord, Bring Me the Head of Alfredo Garcia.
A title (if it fits the story) can be simple. Jaws, Shogun, Cathedral, The Exorcist, Ragtime, Lolita, Deliverance, Airport, “The Swimmer,” Roots, Centennial, It, The Godfather.
In fact, it has been said that most titles on bestseller lists are no more than three words long. (But they have to be the right words.)