This is what I do: First I try to learn as much about the geographical area as possible - because someone who reads the book just may be from there! Don't want to leave a bad taste with inconsistency, set the stage; visualize your hero and your heroine; what features jump out to you? do they have any personal traits that you can expand upon throughout your book? You need to have key elements: the meeting, strong believable characters, chemistry, conflict and lets not forget the L word ... you got it Love... Never forget your telling a love story, and honestly none that I know of didn't have some sort of conflict to over come. Now I am a sucker for Cinderella as is reflected in my writing style; my point is the greatest of loves throughout time had conflict that would have torn them apart had they not found away to over come these obstacles - this is to be said of writing any romance novel. (Historical, Contemporary, Paranormal etc...)
I would be very interested in your thoughts and idea; come lets get together and share!!!