Lately I have heard much about the importance of your book cover. Is your cover professional and appealing? Would someone pick it up? But the same care should go into your title.
Titling is not yet one of my strong points. Perhaps you noticed that I have a project with a title of "Dungeon" and another one that is simply called "BB" at the moment. Obviously, my titles will need revision before publication.
I recently read a post by Jenny the Penslayer called The Title at the End of the Reader's Patience. Some of her tastes vary from mine, but, by the end of her post, I was laughing so hard I nearly cried.
After reading her post, here are 6 guidelines:
1. Pay attention to the cadence. How does the title sound? How do the words roll off your tongue?
2. Your title should have a balance of enough information without telling the whole story.
3. Some words (like "shadow") have been overused in titles. It is a rare title that manages to use these words in a way to grasp the browser's attention. Make your title unique. Make it intriguing (the reader should see the title and want to know more).
4. Your title should make sense. Otherwise it will become the laughingstock of Jenny's blog...
5. Some title sound like they were written by a young fan instead of a experienced author. I haven't quite pinned down the rules dividing the two (likely they are a combination of the other things I have mentioned), but I trust that you, like me, have an intuitive sense of what a title should be.
6. This last point should be a given, but, based on some titles, I suppose it must be mentioned here: please pay attention to your grammar and spelling when creating your title. If you need more information on this topic, find yourself an old schoolbook from English class.
I hope these were helpful to you. I also recommend Jenny's post -- I felt like the list of titles (with her commentary) functioned as a personal exercise in title-judging. Try it.