Starring at her mess with your evilest eye won’t suddenly make her realize that she’s too messy. Instead this is one of those situations where you’re going to have to be confrontational (but NOT hostile) and ask for a compromise. You can’t expect her to go from slopfest to neat freak, but you can ask her to make sure her mess doesn’t invade your side of the room and that she does her best to keep all smells at a minimum. Just asking her to “be cleaner” won’t get you very far. Give her clear suggestions like “please put your gym clothes immediately in your laundry and not on the floor.”