Find as many ways as you can to illustrate how you see yourself.
Start with the most obvious - your appearance and how you like to project yourself through things like your shoes or your hair.
Photographs are a good tool to begin with, as they are most literal.
Gradually become more detailed and specific, notice patterns that start to develop.
Move past the obvious external aspects and start to come to a more subtle place. Your traits and interests.
Become more abstract still by using sketches and collage. Keep going through the layes of "youness", see where it takes you?