Great topic.
Take a passion for learning that has some mix of curiosity tossed in, mix in a bit of aptitude for learning. Now toss that into an environment with the learning label that moves too slowly and out pops an autodidact.
For me, a big key is that I know what is my own thought and what came from somewhere else. I also have a strong internal sense of how strongly anything is supported. Combined with this, if I focus as I think about something, I do not forget my thinking.
Things start with a near-match model in my brain. Really depends on the subject, but a skim of Wikipedia can get those initial hypotheses in place. If it is a relatively fresh topic, then I find the absolute most readable book on the topic (readability is more crucial than content, breadth, or depth at this point,) yay Dummies.
As I read I am working on a model and creating mini-hypotheses as to how close or far anything is from other things. Always drawing analogies, I create little Socratics that get answered or penciled in for follow-up.
Ultimately I am fairly resource neutral, but when available, an expert (particularly one that is capable of listening outside their own thoughts) will often help bridging knowledge.
