Some great insights below from Frank Chen, and generally speaks to me about the wisdom of picking quality people to collaborate with over anything else:
I got a piece of advice too late into my college career for me to use it in college. That advice was, “take classes from the great professors rather than classes whose description in the course bulletin sound interesting.” It turns out that the great professors will make their subject material fascinating, relevant, and engaging. I was a senior by the time I figured this out, so it was too late to re-take all my classes. So I’ve been making up for lost time with my career choices. And hanging around Marc and Ben has turned out the way you’d expect hanging around those two would turn out—it’s been the ride of a lifetime.
— Frank Chen on how he got recruited to work at Andreessen Horowitz.
Raanan Bar-Cohen 
Great advice – speaking as a professor.
I was lucky to learn that early when I happend to get a few really spectacular professors in my first year of college. I think the rule extends to conference speakers as well—if you know the crowd or if you can ask someone who does. Website content can often substitute as a good first impression because someone who writes well online is also likely to teach well.