I'm really not good at them (see above for QED). I have to confess that the titles of both my books (Cassie's Grand Plan and In His Eyes) were created by others. Cassie's Grand Plan grew out of a suggestion from my lovely crit partner Louise, and In His Eyes was entirely the creation of my wonderful editor Megan.
But for my current WIP, I have a title. And it's so awesome, I'm not even going to tell you what it is. Every time I open the file to add to it, I see that title and do a little inner squee at how clever I am. It's proving to be a lovely bit of motivation and encouragement -- there's nothing like going into your writing time already convinced that you are rather a clever clogs.