More About Why Details Matter
You may hear some writers declare (I don't believe I've ever heard an author say this) they write their novel first and then do research. I suppose I must grudgingly admit this is possible, but the truth is it ain't likely to result in anything good enough to publish.
I bet your hero probably does something or other for the War Department that sounds vaguely spy-like... You don't really know what the War Dept. did, exactly, so you can't really say what your hero was doing for the war effort.
Writers who think they can research later don't understand the complexity of writing a novel good enough to publish. Let's say you're writing a Regency Romance because you enjoy the genre. You know nothing about the era except perhaps what you've read in other Regency romances. Napoleon was maybe doing something annoying to the English, there was a Prince Regent and the socially elite all wanted to go to Almack's. You write your novel based on this and maybe it's not so bad. Maybe you write well enough, and you think you've managed to create some tension and interest between your characters. You've written 70 to 100,000 words, the scenes are tight and the plot keeps you turning the pages. It's a lot of work to get that far.
Without knowing more, I know your characters lack depth. I bet your hero probably does something or other for the War Department that sounds vaguely spy-like. I know your novel is riddled with inconsistencies and gaping defects in historical continuity. You don't really know what the War Dept. did, exactly, so you can't really say what your hero was doing for the war effort. Your heroine isn't the least bit aware that, in fact, she has very little control over her life and you've offered no details to explain how she ended up with such modern attitudes about marriage and husbands.
I also know your novel lacks richness because there are no details to make a scene come alive. What kind of furniture did people have? Well, you don't know so you can't describe an ornate desk that was smuggled in from France. You don't know when (or anything about) Van Dyked sleeves that could get caught on the hero's buttons. Oh, gee, I could go on and on. I'm sorry, but without doing the basic research first, you've just wasted enormous amounts of time creating an unbelievable plot full of ambiguity that you will have to rip to shreds in order to make good enough to publish.