Start with thinking in black & white.
Focus on the core of information and then fill it out further from there.
What's the Header Title? Or is it a left chest logo?
What's the middle body of information, or is it a graphic image? What data is at the footer
(like a catch phrase, location, or date)?
When thinking of the back of the shirt
remember a call to action such as a phone number, address, or website for more information.