Hello Angela, I've been reading back through some of your comment replies and your novels sounds interesting, I love the high Victorian age (I like all of history really but the Victorian age is one of my favorites). I think that having a finished novel is a huge achievements in itself, so congratulations! Are you going to keep submitting it to agents whilst you try something new?
I personally find plotting ahead of time massively important for me. I am probably a bit of an over-plotter - I have every chapter and scene pretty much locked down before I begin writing. I often think of plotting a bit like story boarding for a film, I want the whole book to flow like a movie in my head and then that way I can pace out the scenes, character emotions etc. Of course my plots are often quite simple so that helps:)
Good luck with your new book. Are you in the same time period or have you time traveled to pastures new?