Quite frankly, I myself am not entirely sure how I cook up stuff like that...from what I can tell, the "script" just seems to write itself, y'know? Perhaps all those years I spent playing games with well-done stories (many of them JRPGs) sort of rubbed off on me.
Well that, and as someone in a very sincere and passionate relationship of his own, I have what you could call "skill from experience." ^^;;