Be on your best behavior. Many students who are away from home for the first time tend to "bend the rules" as a demonstration of their independence. Those students tend not to get resident assistant jobs because it's the job of the RA to enforce those rules, and administrators who choose them feel that bad behavior tends to be repeated.
Realize that a resident assistant cannot please everyone all the time. There will be times when you have to take your best pals to task for something they might have done. Being a resident rssistant means that you must be a positive role model, so that you will be respected during those trying times.
Be able to do more than one thing at once because being a resident assistant requires you to be both organized and adaptable. In a typical day, you might have to deal with a fight, an unruly student or two who has had too much to drink, or problems involving sex. Even if you have a major exam the next day and try to hide out in your room, those problems will find you and you must be able to deal with them.
Have the capacity to be tolerant of the students because they are young so they will often exhibit bad behavior. If this quality is not in your make-up, you should not apply for the job.
Apply for the job if you feel you are cut out for it. Many colleges and universities begin taking applications in the spring for positions available in the fall. Find out the timing and application process from your current resident assistant. If you do not get the job, which often involves free room and board, scholarship money or a salary, ask what qualifications you lacked so you can apply again for the following year.