From what i've seen, the best way is to become famous for posting in Memes and Games :P
There are a few moderator type positions for people who are well-known/familiarized with the community, but they are pretty selective and you have to be careful what you say in that position (example: Deep Terror Nami).
As for contributing to and furthering the community, I don't think there's much that any one player can do in a community so large. Instead, I would suggest you focus on building your own minor community. You can post on the forums in Team Recruitment to get more people into a ranked team or a Club (that's how I got into Support Mains Therapy Club). You can also bring in players you meet in game that you feel were friendly and helpful towards having a fun experience. Try to focus recruitment around players of your ranking (if ranked) so that you'll be against similarly-skilled opponents when you play together. Curse chat is almost always better and easier than Skype in case you haven't gotten it already.