I also did several "screen tests" with the character, some alone, some with another character from the series where I created a short one off scene in the environment and "world" of the series without being from the actual episodes just to see what the character looked, sounded, acted like in the world and then I was able to tweak the character's appearance, voice, personality as needed before creating a full episode, a useful technique if you are doing a lot of world building!