Just to get these out of the way.
How do you select modsWhen we decide we need new mods we get together and throw out names to see what people think. After a while the list will get winnowed down to a select few and we'll start to more seriously discuss the candidates. Eventually Gstaff will have a vote, although this is really a formality, it's always been quite clear who we're choosing before this point.
What are the requirements to become a mod?You have to be at least 18 and be a member in good standing. This does not
necessitate a 0% warning level, but certainly someone with past warnings will have them scrutinized.
There are no expectations in terms of join date or post count, but it is uncommon to have candidates who've been here less than a year.
What makes a good candidate?Personally I'm looking for people who have a positive presence on the forums - which generally means someone who is helpful, can handle problematic discussions well, and knows when they need to step back because they're getting frustrated. We want a diverse group of mods so it's hard to nail down exact requirements.
Often people who catch our eye are those active in the forums we feel need more help, but as the forums grow I think this is becoming less of an issue. For example, the Skyrim section is one of our busiest at the moment but almost all of the mods are happy to help out there. Some of the smaller forums don't have a big moderator presence but then these areas require less moderation. Really as long as you're active in the gaming sections I think that's sufficient (or put another way, it is very unlikely that we'd consider someone who spends most of their time in CD).
Being active at sparse times will grab our attention, which generally means the further you are from the Eastern Time zone (which has Bethesda and the most mod representatives) the better. However while this may make a member more attractive as a candidate it's more of a bonus than anything else.
You make it sound like you needed permission.

He does, but presumably from us and not you

Funny enough I suggested we have another of these about a week or two ago.