Be Yourself . You are never going to be Joe Strummer. Joe Strummer was Joe Strummer and you are you, which is not a bad thing. The most attractive thing you have to offer as a bandmate, as a performer, and as someone an audience wants to watch (more than once) is being yourself.
This can be challenging while you are building your confidence as both a player and performer, but listen to your instincts. When your instincts tell you to do it the way someone else does it, listen to the deeper meaning. What are they really telling you?
Practice more? Study the way your hero does it? Improve your craft?