Very little make up at all.
Hair relaxed, wash it, dry it, thats it, tie it back if you have to.
clothing, relaxed look & feel, jeans or skirt, tank top, maybe another one over the top, footwear; flats or thongs (they're called thongs in the country they were invented, there for thongs and not "flip-flops").
over dressing will freak her out and you will get looks. dressing like you're relaxed, just there for the day and its not a big deal, people won't even notice you.