Our one was changed to a 'dinner dance' - casual clothes (though apparently everyone's getting dressed up anyway) and only year 10 students from our school. I have no idea when mine is, the info was on the ground and my dog decided to take a dump on it.
Our science teacher told us to use the reading time well and then, firstly, go through and do all the questions you know and can do pretty easily and then go back and do the rest. Also, remember not to spend too much time on each multiple choice, seeing as how they're only worth 1 mark each...