Races are a very popular and common element to RPGs. A roleplaying game is largely about developing an identity, and races help fulfill that need. So I had humans, elves, a dwarf-like race, a halfling-like race, a giantkin-like race. And it wasn't entirely because I was copying what I knew; I also really wanted to connect with the whole history of Tolkienesque fantasy, which means halfing elflike and halflinglike and dwarflike races. When you're working with that, you're working with an established set of expecations, which in a way gives you more control. Players know what an elf is supposed to be; they aren't going to take your elves in a totally new direction that you don't want and never intended and that doesn't fill a role in the game story.
So I had some pretty typical races. The game setting was different though: it was supposed to be a medieval Arabian, which never quite seemed like it because I set the main town in a jungle, not a desert. I think I'd chosen a medieval Arabian setting for a good reason. I love the medieval stuff because it's so much simpler than more developed settings... travel and information were so limited, and all that secrecy fits in well with storytelling. You can develop tension. What's going on with that cloud of dust over the next hill? We certainly can't turn on the TV and find out, or drive over there in a car. Plus, medieval weapons are more fun, and it's easier to make medieval combat (where it's harder to kill someone outright) more challenging. And the Arabian setting made it different from all the Tolkienesque settings out there; plus I think people really get into desert settings. I can't remember now why I had the main game area set up in a jungle.
It might have been because I really got into a colonial theme. The Humans, the dominant race on their continent, had discovered the new continent of Cerulea a couple hundred years before the game setting. They were much more developed than the local race, the Burrans, who had become very oppressed and were living in squalor. I liked that idea because it's such a huge part of human history, and there are some very interesting dynamics in it. A lot of opportunities for conflict, a lot of roles to play. You could be a stereotypical Human oppressor, or a sympathizer, or a Burran radical, or a turncoat who got rich and only wants to be around Humans. In the real world, our colonial legacy continues to this day (though it's taken a very interesting turn with the Indian casinos now).
After a couple little changes I had the backstory and current setting of the game down, fairly well developed, and that remained. (Check out the old Cerulea website for all of that... and also some very hopeful RP rules coming out of my background as a onetime RP purist.)