Participate.
Join in on discussions, show up for in-person meetings regularly, offer feedback, and help implement that feedback.
Step down considerately.
If you have some form of responsibility in your community, be aware of your own constraints. If you know that a new job or personal situation will limit your time, find someone who can take over for you and transfer the relevant information (contacts, passwords, etc.) for a smooth transition.
Use basic etiquette for online discussions.
Don’t send messages that only needs to go to one person. Keep off-topic conversations to a minimum. Don’t be spammy by advertising or promoting personal projects which are off topic.