I'm going to take this summer's blogging time as an opportunity to dish out some periodic advice about what to do before, when, and after you move in to IU. Take it with a grain of salt, as everyone's experiences are different.
Tip 1: Scheduling Classes
Do your research on classes BEFORE you go to oreintation. Picking classes is probably one of the coolest parts of the two days, and having a general game plan and having back-up classes will make it go much more smoothly. Stay flexibile; since you are registering after all of the sophomores, juniors, and seniors, chances are that your game plan is going to be impeded by a few full classes or overlapping times. When I scheduled, probably three of my top five picks were full, but having a list of other interesting and/or required classes really helped me avoid a sloppy schedule. Also, don't stray away from super early classes just because of the time. People act like 8 a.m. classes are the most terrible aspect of college life; true, they can make those cold winter mornings a bit harder, but the sooner you get up, the more you can get accomplished during your day.
Have fun scheduling!