Don't try to use your arms to pull yourself up...use your legs to drive yourself up and use your arms to guide yourself, does that make sense? You will have a longer day (and a LOT less soreness) if you don't try to use your arms to pull yourself all day.
Trust your equipment but always always always double check it, then double check your belayer's. Always.
Don't worry about looking like a dork in a high waisted harness. It's designed that way for a reason.
Wear yoga pants & a tank top to give yourself freedom of movement. Plan on not wearing socks, and yes, climbing shoes are supposed to (sort of) hurt a little.