Depends on which civilizations you're talking about
1st, Say something along the lines of "The (Civilization on one side) is (Their characteristics) and are (Ruthless, Peaceful, etc. Describe their demeanor), but what makes them so different from the others? The (Other Civilization) is involved in (Something similar to the first), which (Civilization 1 ) takes part in as well. But what are their differences?"
Sorry if this was slightly confusing but I write Compare/Contrast essay thesis statements literally every day and I've gotten 100% every time.
Hope this helps :)