How do I tell an ESTJ from an ESTP?

So I'm an INFJ, and I don't know any of either types that I know well in real life. One, the ESTP, would be my dual, and the other, The ESTJ, would be my conflicting type (in socionics).

So, sure as I am that differences are astounding, what would some ways to tell if a person is one or the other?

Edit: For further clarification, I find it hard to picture an INFJ - ESTP relationship where the two would have anything to offer each other. INFJ's and ESTJ's hating each other makes perfect sense (not saying they HAVE to hate each other), but the ESTP - INFJ dichotomy seems difficult to swallow.