Remember that the resident advisor is just a student like you. They are upperclassmen, but they were once in your position. They are there to help.
Find out the resident advisor's schedule. Some keep these posted on their door or bulletin boards. They have lives and classes and are not available all the time. Be courteous. Ask when it would be a good time to get together for your discussion.
Take your concerns to your RA. Sometimes just taking the plunge and talking to someone is the best method. Tell them your concerns and ask them your questions.
Get involved in activities. For some it is easier to approach people if they are involved in something. Resident advisors often have activities for dorm residents. They also know of other activities on campus.
Ask someone else to approach your RA. If you find you are too shy to approach them yourself, consider asking someone else to set up an appointment to speak with them. Just make sure you follow up with the appointment.