Finding suitable staff for websites is tough. It's far more difficult if the staff does not get paid.
Personally, I let people know that I am looking for staff and that I am accepting applications. After the deadline, I check if everyone meets the requirements. People with inappropriate behaviour always get rejected. In the end, I select people who are capable, willing to help and mature. Of course, previous experience is extremely advantageous.
In addition, I do not believe that there are good staff members. Let me explain this. One staff member may be professional and polite, but also inexperienced. Another person may be experienced, but not sociable and friendly. The best staff member is the one who can combine the experience and the professionalism with the willingness to help and to have fun without making any mistakes. However, that's not realistic. We are humans and we always make mistakes. There is not a good staff member, there is a good staff which is composed of numerous different people who work hard, try their best, make mistakes and try to fix them.