I have to admit, I'm a cover girl. Let me clarify. Not a beauty queen, fashion model, Halle Berry, ANTM kind of Cover Girl™. Rather, a "'kə-vər 'gərl: n. a female who is a sucker for killer book covers" kind of cover girl. Maybe you can't judge a book by its cover, but when browsing, a sharp, snappy cover will get a book into my hands for at least two minutes--long enough to read the back cover copy and maybe the first few pages, and more importantly, long enough to make a decision on purchasing aforementioned book with the sharp, snappy cover. Prior to publication, of course, you don't have the luxury of a professionally designed cover to help would-be buyers (agents, editors, etc.) make a "purchase" decision. However, you have something even better: your title.
"Wait," you may say to yourself. "But isn't the point of the query and submission process to prove the quality of my plot and writing--not that I can string together one to five pithy/profound/intriguing words for a title?" Yes--of course. When I'm reading query letters, I'm reading first and foremost for the substantive goods: plot, voice, characters, writing style. If a query matches up with what I'm seeking in those categories, I'll request to see more ASAP. But sometimes, I might be on the fence after reading a query letter. Maybe the plot sounds intriguing, but the writing's a little off. Or maybe the plot sounds a bit generic, but the protagonist sounds compelling. It's then that a title might tip the scales in your favor. If the title piques my curiosity, I'm much more likely to request material at that point.
Finding the right title can be a difficult process. It's worth spending a bit of time brainstorming to make sure that your title fits your work well. But don't stress too much. A title will certainly never break whether or not I request to see a partial manuscript after readng a query. However, it just may make it.