I just thought I'd take a few minutes to explain some of the core guidelines we look for in potential Staff members. If you don't fall under some / any of these groups, then you have something you need to work on.
1. Positive Community Image - One of the most important things for a Staff member to have is a positive image with the community. This means that you cannot be public enemy number one: you have to have mostly friends and only few enemies. One way I can very easily tell how cut out someone is for being Staff is this: If I see in their staff application that most of the replies are saying how the guy applying is a moron, a jerk, etc., or he's known to cause trouble, then he probably isn't really fit for being Staff.
2. Thorough Community Interaction - Another key aspect of Staff is that people need to know who they are. A player who is mainly a recluse in some log cabin on Survival server probably isn't the best pick for Staff. A very outgoing player who doesn't seem to be on anyone's bad side, however, is a perfect example of Staff: It demonstrates that they possess the abilities to make friends and stay connected with the community.
2a. Tenure (of a sorts) - This is closely tied in with Community Interaction. Most candidates who are asked to become Staff have been around for a while. This isn't to say that seniority is everything, far from it. Candidates simply need to demonstrate a commitment to the server. If it is your first day on the server and your first post on the forums is an application for a Staff position, you have very little chance of consideration. Generally, 2-3 months playing on the server is preferred before a candidate will even be considered. As was said in the previous section, people need to know you but they also need to know you're going to be around for more than just a few weeks.
3. Understanding Your Position - What is the job of Staff? If you cannot answer this, you aren't ready to be one. A Staff's job is to ensure prosperity on the MineRealm servers, be that through repairing griefs, aiding new, confused guys, keeping chat under control, managing disputes between players, etc.
4. Keeping Cool Under Fire - Probably the biggest one we look for. What this means is that Staff have to be able to take the BS players dish out at them, and can be sure to not dish BS back at them. By this, I don't mean that Staff should submit to insults, far from it. But they need to demonstrate that they doesn't take the idiotic antics of players personally.
I'm not trying to serious-face and say it's a serious job with serious business and serious cake, but you have to understand that Staff still need to have certain aspects about them. I'll add more of these if I think of any.