You can't you need a forum moderator to do it.
you can;t become a mod but a assistant you can.
To become a moderator on creaturebreeder.com you must first become on on the official forum. If you become a respectable poster and don't cause any trouble, you can be asked to join the team. Always be helpful on the forum and make sure to follow the rules and post in the appropriate places.
This is only through invitation. There are no applications for moderator. You will be invited via the messaging system. RuneScape looks for players who follow the rules, basically. If another player tells you you are being considered as a moderator, he is trying to scam you, and should be reported. Also, if you receive an email about being a player moderator, it is a scam.
you need to be a member to become a moderator first
you can't become a mod any more. Jagex had a forum you could fill out to become a mod but now you cant do it.
sign up to the forums and click on how to become a moderator and follow the steps and become a moderator
To become a moderator, you must be reviewed and approved by the owner or another moderator.
Do NOT ask to be a mod! Please read the Newgrounds FAQNew answerLots of people are wondering how te become a moderator or how they are chosen. It's not a matter of having something, like having more then 5000 posts or being a member for more then a year. No, it's a matter of your appearance in the forum.'Real' moderators stand up on the first day they are here in the forum. They are doing something extra then the other member, they are helping other members, help thinking about how to make this forum better and they are here on a regular basis. If you look around you can find some these members. It are these members that earn the most respect from others and if a moderator is needed, these members are recommended for the job.So it's not a matter of how much you have done or how long, but what you do and how you it.Reference link http://forum.letssingit.com/topic/20313/how-to-become-a-moderator/1
you send them a bill (money) in the mail to them and the forum you print off the internet.
One which is not radical in either direction.
You should check this on Runescape forum.