Before you take on this wallpaper installation or 3d installation journey,its very important to know your measurements. The right thing to do is measure the length and breath of the wall or whatever area want to cover so that you can be accurate.
The first thing to do before you select a colour is to understand the purpose of the space, how do you want to feel when you're in that space? If you understand the kind of emotion that you want to feel it will help you select the exact colour that will create and achieve that emotion you desire.