Working on bigger FOSS projects - most of them unfunded or barely funded (i.e. grassroots initiatives) - I collaborate all day every day. Some projects have 2-3 collaborators, others have 10s-100s. Every contribution is a good one, because even when something is immediately rejected because it's malicious or just plain dumb, the response helps: boundaries are clarified.

To me the most important thing in collaboration is transparency (in software the only exception to this is vulnerabilities) implemented in the most inclusive way possible. Most often this means you just work together in public. No bilateral crap, no gossiping behind backs, and a clearly documented process.

That said, I still learn every day as new situations arise within projects and I try to ask questions when something is odd, and keep an open mind to whatever gets said. Even when things sound like drama, there's often a signal that can be turned into improvement.