It is completely up to you what you want to wear. Some people will dress up others are coming straight from class and just wear what they did to class. You don't have to bring anything if you don't want to. I know some people will have questions that they have wrote down just so that they don't forget them. As of what to ask, whatever you don't understand. I know some presentations will talk mostly about the program in Florida, so if you are thinking about the one is California, you may what to ask questions about living expenses, hours, the best way to get to/from work.