I guess the really savvy marketers use a lot of channels but these days I don't want to spend that much time on it. I find twitter useful for interacting with other developers and getting useful dev and research info. I had good results with Facebook pages but I'm anti-facebook now so I got rid of it (same with Instagram). I'm sure others here have good ideas, e.g. I see a lot of people use Discord. Also, I've checked out local gamedev and developer meetups and those look like good places to show your work and hobnob with others (even maybe team up!)
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I don't know what's available in your area, but here (in Las Vegas) there's a recently revived IGDA meetup, occasional game jams, a Unity user group, and a monthly Demo Day where developers give a five-minute presentation of their projects. There's probably more stuff, but I don't look around that much.