well somethign in the scifi genre is really hit or miss, with the latter being more the case usually. but if you got somethign good going and you really believe in it, flow with it. id say that the best way to come up with some ideas is either shoot the shit with your friends (pardon the language), or to completely and utterly zone out, just let your mind wander. i think where you have to start is with the characters first, and like the person above me said, dream journals might be a great place to start, or base characters off people you know. then when you get something like that, put the characters into base movie or story situations (ie wars, love stories, small town to big city, etc), and i think you could cook something up from there