science fiction cultural elements

I've gotten some fairly good feedback on my current free novel, but I'm not sure if the source is a big science fiction fan. I don't want to undo the mood with lots of technical stuff, but I suspect I need to put in just a little more science fiction, if only a little more alien descriptions of the characters, long faces, one less finger, but more importantly, a little more alien thought pattern and cultural elements: what makes the military officers military? How to they express authority? Not just the shape of a salute but a reflection of some other aspects of their culture that i have barely begun to explore here. I need to spin off some independent short stories to experiment with some ideas. That has always helped on the stories that I have been developing longer.