Even monsters need a name. You wouldn't just call it, "Hey, you." The same goes for your creation; your novel, memoir, short story... whatever. My recommendation is that you settle on the title for your piece before you start writing. There's something about having a good title in place that legitimizes your work in your mind and makes it possible to move forward. On occasion I've tried to write a book without having the title down, and it just never worked. I was paralyzed by indecision, uncertain of where I was going or even what I really wanted to say. But once I have my title, my wondrous creation has at least the potential to come to life.
A title is not (as a rule) copyrightable. If you do search on Amazon.com or one of the other online booksellers, you'll notice that titles often overlap. "Answered Prayers" is the title of books by Truman Capote, Danielle Steel and Julie Cameron. Each a different genre. Because so many books are and have been published, it would be nearly impossible to come up with something completely unique, unless you choose a title that's fairly long. In that case you might have a case for copyrighting, but even then it gets tricky. Take the title "Gone With the Wind." Everyone knows that one. You probably couldn't get away with writing a novel and using that title. The guardians of Margaret Mitchell's estate would lilely have something to say about it. But say you're a doctor who has developed a new medication that controls flatulance and you want to call your book about it "Gone With the Wind." It's a very different type of work, so there shouldn't be a problem.(Though there might be a general outcry of protest.)
Back to long titles. "The Curious Incident of the Dog in the Night-Time" by Mark Haddon is certainly an exceptional title, and one that could not legitimately be re-used. Same goes for "TheDivine Secrets of the Ya-Ya Sisterhood" by Rebecca Wells. With titles this unique, it would be nearly impossible to make a case for using either one for another piece of writing. You could, however, use your own title as a play on someone else's work. For example, the bestselling book, "Three Cups of Tea: One Man's Mission to Promote Peace . . . One School at a Time" by Greg Mortenson has recently come under scrutinity for it's truthfulness (or lack thereof). In response to the scandal, author Jon Krakauer has penned an essay titled "Three Cups of Deceit: How Greg Mortenson, Humanitarian Hero, Lost His Way." Clever.
If you have a title in mind, just do an online search to see what else comes up. If there are several books out with your title it might be best to think of something else, to avoid confusion if nothing else.
I like long titles. They're fun, not easily duplicated and tell something about your book. Long titles usually follow a rhythm that includes a beginning, middle and end. The middle acts as a bridge that connects the other two parts. The above mentioned "Divine Secrets (beginning)of the (bridge) Ya-Ya Sisterhood (end)" is a good example. So is "Fried Green Tomatoes (beginning) at the (bridge) Whistle Stop Cafe (end)" by Fannie Flagg. And "The Guernsey Literary (beginning) and (bridge) Potato Peel Society (end)" by Mary Ann Shaffer. I could go on.
These are all great titles with a lot of pizzazz.They stand out, and once heard are not easily forgotten.
"What no wife of a writer can ever understand is that a writer is working when he's staring out of the window." Burton Rascoe