honestly, just be active! verbal and active.
in the forums, this looks like making contributions to topics with comments that push the conversation forward - advice, anecdotes, jokes, whatever the topic suits. its also good to start your own threads, like this one, to ask questions you want answered or discuss elements of comics / wider storytelling and art that youre interesting in.
on tapas, that looks like posting consistently, and commenting on other people's comics. i dont mean 'looks great, sub to mine!' (do not do this it looks bad), but just openly engage with and be passionate about the comics youre passionate about. and yeah, definitely search out smaller comics you love, because thats where being a good reader turns into networking. i also find that giving tidbits of feedback helps build bonds between creators - but be tactful there. similarly, asking questions about a creators process is a great way to build connections.
also, promote other people's comics. gush about them in the description of your own comic or on your wall, or in certain threads on the forums. this is particularly effective during tipping events - youll find a lot of creators share links to all their favourite comics as tipping events come around, to share around the seasonal joy.