Lol you are free to wear WHATEVER you wish. There isn't that much you need to do really, being polite is always good, that's just customary though. Learn the money system and you'll be okay. Where abouts are you going?

Oh and voltage powers are different, so get your adapters and whatever.

Also this time of year is usually quite nice but there's always one or 2 days which catch you off guard and are cold and rainy, so make sure you bring a coat or a jacket or something.