Thank you both very, very much, Medievalist and Chase! Really, I can't thank you enough for the advice and recommendations.
I will pick up a copy of Little, Brown and one by Diana Hacker. I do have a book on grammar around somewhere, I will dig it up too. Perhaps it is one mentioned; I don't remember the title.
Unfortunately, I won't have a publisher to turn to, as I'm self-publishing. Everything I've read on self-publishing advice, though, says you MUST hire an editor, even if that's the only thing you spend money on. That being said, I'm still going to try to go as far as possible on my own with the editing process. But I've read self-published books with typos and it comes across unprofessional, and must be embarrassing to the author. People are unforgiving about typos in published works, and one or two can be very off-putting.