One key to getting this right is to examine your characters' motivations. Why are they acting the way they are? Is it something we can understand? I've long thought Woody from Toy Story is a truly great character. Why? Because his jealousy when Buzz comes into his life is understandable. There are very few of us, regardless of our age, who haven't been jealous of something or someone in our time.
Look at how your world is governed. Is it a democracy? Is there a tier of local government? What are the politicians like there? (And there will be politicians somewhere along the line. Where there is any kind of power, no matter how minor, politics and playing people off against one another will come into it. Sad perhaps but again this is something we all understand and will help make your world seem more real to your readers).
So think about emotions. What are your characters likely to feel and why? (This is one reason why the Cybermen as a concept are frightening. The removal of all emotions? Those are what make us human. They can also make your Species X what it is and differentiate them from other character types in your fiction).