I've joined a community and read the rules. More than once even. I've lurked in the community for a while. Occasionally, I've poked my head out of a dark cave and even said a few things. I doubt they've been memorable, but at least no one told at me to get back in my hole. I've voted in community polls, but I don't feel like these have been "drive by" votes, because I stick around.
I have customized my avatar and profile, but I'm not sure how else to participate. Jumping in to conversations where I don't know the participants isn't my style. I feel that I know the topic, but I am not the expert that other members are (or at least play on the internet).
What can I do, as a user, to increase my participation in a community? To make this question more specific, assume that it is a professional community with a minimal amount of off color topics/memes/etc. I'd say think something like Stack Exchange, but it is not a Stack Exchange community so I don't want answers specific to that particular community.