Surprisingly this was a fairly easy part of creating my book. Firstly, I just want to make it clear that you should never title your book before you write it. I had this really cool idea but my book went in an entirely different direction than I first planned. Also keep in mind if you decide to create a sequel, it has to fit. Nothing too crazy to set it apart.
I have heard and read about many authors and sites that tell you to check out the best seller list or lists from your genre of titles. I don't agree with that. I think once you read other book titles, your subconscious picks up on that. Use your own head. Figure it out for yourself. I recommend after you're down to under five titles, then look at a list and see if your book fits in.
I don't think a title should just be about if it fits into a category. Let's be honest, it's not cool to fit in. You want your book to stand out and be different. Fitting in is overrated in my mind. Pick a name that people will remember and can easily say. I can't list every book I've read but certain titles stick out.
Depending on how you are publishing your book, keep in mind that editors or publishers can change your title. So don't fall in love with it. I remember reading an article about The Lord of the Rings. The last one was going to be named, The War of the Ring but the publishers vetoed that and changed it to, The Return of the King. If you're self publishing then don't worry, you can do whatever the hell you want.
I found this site. It's a Title Generator. It's pretty fun to play around with. It's good if you want to brainstorm and pick some random ones. You can arrange the results by genre which is cool. I don't know how it does it but the names are unique and interesting. It's worth taking a look at if you're in a bind.
Happy hunting for a title! TL