find a community doing something you are interested in. get on the mailing list- see who is answering lots of questions in a fashion that suggests they know what they are talking about. see who is making the changes to source. see who has an good reputation in the community.

that is a good place to start from. maybe the community has crappy standards and the people who look good there aren't really that good but if they are better than you, you can learn and then branch out into other communities. learn learn learn.

just make sure you don't pigeon hole yourself into one community, make sure you eventually sample from a wide range of communities ( but that takes years ).