Have you had good experiences working with anyone in the past? Is anyone else involved in your community who you consider to be moderator material? Do any members of this community strike you as respectful, intelligent, and rational? Ask yourself these questions. The selection of staff members is a very delicate process, and it must be treated as such.
Try and make sure they are established, committed members who you can also trust. It's better to find staff from your memberbase rather than from all those App topics.
I try to hire staff I know in real life, especially if it's a co-admin. But if you can't do that, then hire experienced members on your forum. I've had two forums fall apart on me due to staff disputes. Don't let that happen to you.