What are your opinions for finding staff for a server?

I've run a few DarkRP, Sandbox, TTT servers before. In my personal experience, I choose my staff from those users that have played on the server before and for quite some time, or if I have a good mutual relationship with them. I generally had some 'trial' ranks for them to have and they'd be under supervision to see whether or not if they were up for the rank. As for the decisions that I take upon my own staff are dependent on whether or not if it's their first offence. If it's the first one I'll be more lenient, but if things keep carrying on in a bad way, then I'll have no choice but to be more harsher on them, especially on the higher ranked staff. On the contrary, I generally have the policy of just giving them a warning first, and if it happens again then their actions will have consequences.