1. Walk in expecting to lose. If you win, bonus!
I go into battle with this mindset allot. It seems to help me not only have fun, but also relaxed. The more relaxed I am and the more risks I am willing to take often end up in me winning more games.
Very backwards thinking but it helps. If we stop thinking we have the cat in the bag, (which, btw way, I don't like when my heroes put me in a bag... thank you.) then we have nothing to lose but our dignity. This is good.