Write down short thoughts about your book. Think about what you are trying to say within its pages as well as what the main point is and the readers it's targeted against. Write these down. Study the words you have written on these pages.
Decide whether you want the title to relate to the book or not. This is something that should be left to the author. Some unique titles have nothing to do with the book but it can become parallel to it in some manner.
Circle titles. In your list of thoughts and snippets circle the ones that sound like good book titles. Consider books you have read and seen, thinking about what makes you remember those titles and what made you want to pick them up in the first place. Ask yourself if your titles do the same and work on them until they do, replacing words and phrases as needed.
Pick the top five that stand out the most to you. If you have your own website have readers vote in a poll. Ask your family and friends which one is their favorite. Send a note to your subscribers -- if you have an email list, for example -- giving them a quick blurb about the book and the possible titles. See what the majority ruled on.
Make it easy. You want your title to be simple, to the point and easy to remember. The easier it is to remember, the easier it is for readers to share your words with others. Keeping it easy makes it marketable. If people can remember your title and how it struck them, you have an instant word-of-mouth marketer that will promote your book title.