There isn't a whole lot I can say here without stepping a bit on jflory's toes but I'll give it a go. Check out his guide at the bottom of this one! The most important thing in choosing a staff member is, quite bluntly, how they work with people and how good their personality is. I find this is simply fundamental to being a staff member. Now don't get me wrong, the experience & ability of the staff member are also extremely important it's just that those aspects of a staff member can be taught and embellished over time. You can't really teach someone their personality. Next to personality I look for their competence in a situation, you can often find out a lot about a person by giving them a problem verbally (Skype is a good option!) and seeing how they react on the spot, if it's a good reaction then that person is competent and can be trained easily. I highly dis-advise you to promote anyone to staff based on emotional or financial ties unless you trust them and know that they can perform as if they do not know about how to correctly staff a Minecraft server, you will have to teach them. If they aren't competent enough and are left alone to deal with something such as a bot attack, how do you know that they will effectively be able to ban them?
What are you talking about?
What point are you trying to make?