You can keep a conversation going by asking the person questions that requires an explanation rather than a "Yes" or "No" answer. You can also try to remain focused on what this other person finds to be interesting, and from there, take it off.
No disrespect, but i disagree with marissa. Thats not gonna help. You need to ask the other person about his or her self. Find things you have in common, talk about those things. Let him or her talk, show interest, ask more questions.