I think @inteja had a lot of good points. A working prototype of some sort can really get the ball rolling in peoples minds.
From personal experience, it’s not what you know…but WHO you know. I think getting out there and making friends, contacts is a great way to get exposure. You never know when one of those friends might be interested to help out. Or maybe they know someone who would be interested.
Ok? So how do you do that? Social media/forums like you mentioned is definitely the way to start. Something I did a tad in my earlier years was do is group game jams! While you won’t walk away with a finished product per say you will make tons of contacts who know how you work and may give even more insight. There’s lots of indie conventions where devs mingle and share ideas.
Personally I love Twitter a ton. I think it’s actually a great platform if you want to market yourself. Discord also has lots of developer channels and communities.