I'm sure there are PLENTY of people here to give you suggestions, but we have to know what to suggest. Nobody wants to write a detailed post about how to achieve Mystique's scaley look from the live action films, only to be told you are doing the comic version. So give us some guidelines! What version are you doing? What is your budget like for the project? Any materials you absolutely want to avoid/include? Are you going for 100% accuracy, or are you okay cutting corners in favor of keeping it cheaper/easier? Etc.