World Building: Races. One of the toughest things and most important when creating an entirely unique world. It is also one I am struggling with currently. In a lot of films and tv series currently on air the trend seems to be going towards human dominated worlds with no other fantasy races. Even if they do have fantasy races they are generally generic elves, dwarves and orcs. I am wanting to do something different… unique. A tough thing to accomplish when most ideas have been used to exhaustion.
Writing an all human world would be the simplest of all routes to take. You can still have an amazing level of diversity and there are several instances throughout history of varying cultures.
The complications come in when it comes to adding in several distinct races. Most of it in their design. The details are in the history and cultures though that comes with no matter which way you choose to go.
You can go further with each kingdoms history and the culture they live in. The most important thing to remember is to keep copies of everything to reference when needed. Personally I use a binder and printed out copies to quickly pull out whenever something important is needed.