Okay, so, you are suggesting I figure out who the project lead is and email them as my first step?
Some projects use mailing lists, forums or even irc.
Open, group-based forms of communication are usually preferred because it allows anyone qualified to respond instead of pinning it on a particular person.
Larger projects, especially corporate- or foundation-backed ones, might have less-technical staff dedicated to the web presence/PR/outreach etc. which might use other communication channels than the developers.
> Then I try X and it blows up in my face because it turns out you only do X under (long list of conditions that no one ever told me and assumed I knew).
You don't necessarily have to know. Some exploration and just asking for pointers is often required.