Find out what your college roommate will bring to the dorm room or apartment you plan to share. For example, ask if she has a microwave, television or a mini-refrigerator or if you need to bring yours. Dorms, in particular, typically do not include much more than beds and dressers, so you will need to coordinate who will bring other furnishings. In addition, ask if she has any decorations she is planning to bring to see if they will work well or clash with the décor you plan to use in your shared space.
Learn what your college roommate's goals are and what she plans to study. Find out why she chose to attend that particular school and where she comes from. In addition, ask her about her activities -- the kinds of clubs she was involved in during high school and the extracurricular clubs she plans to join while in college. This will give you an idea of how busy she will be and possibly the time frames she will be away from your shared space. Ask her what she expects from college in terms of building relationships and preparing her for the workforce or graduate school. Also, ask her about her favorite books, movies and foods to see if you have anything in common.
Ask your college roommate her personal habits such as her tendency to be a night owl or more of a morning person or her desire to play music at night, which could affect your sleep schedule. In addition, ask her how she feels about sharing items such as school supplies, clothing or food, and ask what her tendencies are in regard to keeping the floor clean or using a laundry basket. In addition, find out what her views are on bringing over guests of the opposite sex or the same sex and how long they are allowed to stay. Ask her what her pet peeves are, and let her know what upsets you as well.
Try to find out what your college roommate's views are on your personal religion or philosophical beliefs or if she has personal beliefs you would like to know about. By knowing her belief system, you can avoid doing or saying things that offend her and vice versa. Also, ask if she smokes or drinks and how she feels about living with someone who does or does not.