Hi james, welcome to the forums. You should definetly stay away from anything that will give you explosive diarrhea. As far as the background, traditionally it would be wind bars and clouds. There are also flowers added to keep the dragon in a calm state, usually cherry blossoms. Colors for the dragon its self are usually red, green, blue, or black. I’m probably missing a color, but each color has its own meaning. That’s just the cliff notes of the dragon. Hope this helps a little. Good luck.
Patrick