Samuel Clemens once said "The difference between the right word and the almost right word is the difference between lightning and a lightning bug."
This is just as true of titles as it is of the narrative, and in some cases the right title may be even be more important.
The trouble is, coming up with the right words for a title can be hard. Really hard. Rarely is it like the prose, where the perfect words seem to just tumble out of the aether and onto the page.
I think part of the problem is that there are no hard and fast rules when it comes to titles beyond "it has to fit the narrative". You wouldn't call a book about a zombie uprising Buttercups & Kumquats unless that sheer randomness somehow worked with the narrative.
I realize, of course, the title you have now may not be the one it ends up with by the time you've gone through everything, but that doesn't make it any less important right now.
So what makes for a good title?
As noted above, a good title generally shares a theme with the story. The last Hercule Poirot novel was titled Curtain and the last Rebus novel was titled Exit Music, both fitting the "end of a series" thing rather nicely.
But sometimes the fit isn't quite so blatant. Think about the Twilight series for a moment. Now think about each of those titles in relation to their content. Each title still fits the narrative seamlessly, even if you wouldn't be able to guess it just by looking at the titles (okay, Breaking Dawn may or may not be an odd duckling).
Sometimes, though, a title doesn't match the narrative like that. Not really. Pick and choose a Harry Potter title. It's telling us what the story, or at least a key element of it, is rather blatantly. Plenty of books are named simply for characters, e.g. Eragon or Will Grayson, Will Grayson.
When I first brought this idea up in December, I was planning on doing a series of posts about titles. The more I think about it, though, the more I realise a series would just be unnecessary padding.
I can go on all day about any titles you want and find threads that link them all in some sort of pattern.
The truth is there are no hard and fast rules when it comes to titles.
A title is your narrative. Snappy, long-winded, thematic, eponymous, they all fit their contents just as perfectly as any of the words inside fits the story perfectly. Finding the right word can be difficult. It can be difficult in the narrative and it can be super extra difficult for the title.
Now, your prose isn't perfect. If it were, we wouldn't need editors. But trust in whatever part of your mind gave you that prose, and you'll have the perfect title. The title is just can extension of your prose. An extra word or eleven at the beginning of your story.
Choosing the right word is the difference between the lightning and a lightning bug.