I find that a working title does wonders for the book. For you, the writer, it establishes a theme that's supposed to be brought forward by the elements of the book. Here are a few tips on how to pick a working title:
- Remember the genre you're in. If it's romance, pick something that is romantically corny. If sci-fi/fantasy, pick something sci-fi/fantasy and make it corny. (i.e. Lover's Spring, The World's War to give an idea)
- Make it short and easy to remember. This way, when you save your work in progress, it will be easier to find rather than MyBook1,000,000 or version10.14.
- It can rhyme. Try rhyming two words that sum up your book, a la Dr. Seuss style.