I'm not very good at explaining what capitalism is, much to my own chagrin. I've learned about it by reading Bastiat and Smith and listening to podcasts by Tom Woods and the like, but I'm not a teacher by nature so aside from asking others to go to the same sources, all I can do is start a list of all the things that I thought were capitalism, that weren't. So without further ado....
WHAT CAPITALISM IS NOT
Capitalism is not "Too big to fail."
Capitalism is NOT lobbyists, or politicians, for that matter.
Capitalism is not tarriffs (whether they're leveyed by Tokyo or Washington, Berlin or Beijing)
Capitalism does not take away from other people when a person benefits from it...
...in fact, if both traders do not believe they've benefited from a transaction, that transaction by definition is not a capitalist one.
Capitalism is not force.
Capitalism is not slavery.
Capitalism only works when each party participating is doing it of their own free will (which is why in most societies it's difficult to keep. Human nature often leads us to forcing others to do what we want. That's democracy, not capitalism. You can have capitalism in a democracy; it's just hard.)
