It's necessary that you establish relationships beyond the bubble of authors, agents, and house editors. You need the dev editors, the copy editors, and the proofreaders. You need the artists, the designers, and the formatters. You need contacts at the distributors for when gremlins strike. You need the reviewers who deign to support self-published authors. You need narrators, ad designers, video developers, and tax folks.
You need to know who's good, who's reliable, who's flexible, and who's affordable.
That's everything you need. What do you give? Introductions. Guidance. Respect. Credit for jobs well done. Gratitude--never underestimate the value of a Thank You.
Always, always, always provide professional responses.
Personal restraint and decorum are the underlying differences between fostering relationships in a professional network versus expanding a group of friends. With friends, you can let your hair down. You say what you think, what you feel, all with minimal (if any) censorship. Not true about professional networks. No snarky asides about people in your community. No sniveling or sniping just because you weren't included in an anthology call. No bad-mouthing the work then trying to soften your rebuke with, "but he's a nice guy." And for gods' sakes, no laying your burdens at everyone else's feet and expecting them to resolve your issues.
It is very easy to say very nice things about people with whom we enjoy working. It's not as easy to discourage people from dealing with incompetent buffoons while remaining on the high road. There is an art to it: the art of Respect, Redirect, & Recommend. If you don't like the work an artist did for you, you don't disparage their talent. You respect the individual by noting something good they did then redirect the conversation and recommend an artist with whom do you like working. If you don't believe the quality of edits provided by a particular dev editor was up to par, you respect the person by pointing out a strength, then redirect and recommend to a dev editor whose work you value. If you're asked about a known predator, the respect shifts to the people who have done the vetting and verification that allow you to redirect the inquiry to a valid source and recommend an alternative service provider. If you don't know an answer or a contact, it's okay to say so. It's no shade on you.
There's a difference between providing recommendations/cautions and spreading gossip. A classic example, "Well, I heard that Pimpy's Promos totally screwed up the order and ruined Ethel's signing." Professional caution or gossip? Depends on whether or not you have personally verified the story with all parties involved. Do you know if there was any effort on Pimpy's part to rectify the situation? Do know if Pimpy provided exactly what Ethel requested, but Ethel's the one who made the mistake? You might share the unverified gossip with your friend, but you shouldn't say it to a professional contact.
Always be aware that the community of freelancers is well connected--for better and for worse. As James said yesterday, don't be THAT GUY.
You might not be courting gatekeepers, but you are building your own pre and post-production publishing team along with building your reputation as an author among peers and providers. Be the client with whom you'd like to work. Remember to give and take when networking. Remember that the contacts you make while networking are not your confidants or your cronies. They are your professional peers.
Networking is all about Respect with a healthy dose of Redirect & Recommend.