Asking to be a mod and doing so just because you want to get paid isn't a good idea and is probably the opposite of what you want to be doing. Report a lot of posts with a good accuracy and be a very active member of the community and if you're needed an admin might ask you eventually, but I wouldn't make it a goal to become a mod as you'll likely only be setting yourself up for dissapointment and might be waiting a long time especially seeing as there's a couple of members with thousands of posts reported and will probably be the next in line when the admins feel like we need more support.
Like on most big forums you can't just follow some rules and you'll become a moderator. They (admins and staff) will choose you if you hard work, help a lot of people, do some nice tutorials, etc. That's how I think it's made, but I can be wrong.
That's what happened with me. I wrote up this epic guide and theymos said "that's a sweet ass tutorial you created... want to be a mod?" and I said yes.