Greetings!
Creating alien, non-human races and cultures can, at first, seem daunting to create. As for knowing or not knowing human attributes, certainly, there are numerous tendencies that are universal, very wide-spread, as well as historical. Dig into studying History. History is the study largely of human nature, and human nature doesn't change. Technology changes, outer trappings change, but the essential human nature remains.
In concerning alien and non-human races, I usually detail the various appropriate non-human natures of different kinds of animals and creatures--reptiles, dogs, insects, birds, fish, whatever. There are plenty of non-human traits and attributes. Some are humorous, some are horrifying, while many are simply different, being tailored appropriately to the creature's form, environment, and mode of living.
Semper Fidelis,
SHARK