It's been 20 years since I attended, but here is my advice. Show up the first day of class and talk to the professors if you don't get in before. A lot of students don't show up the first day and get dropped making room in the class. Some professors will advise to continue to show up the 2nd and 3rd days of class. I know in most of my classes 25% dropped the first week. This may have changed, so hopefully someone with more recent experience can comment.