"What I would suggest, if you wish to cut down on your response time, is to steal stuff from other folks. Steal things from my newsletters. Go to Catholic.com (Catholic Answers website) and use their search engine to look for articles on whatever topic you're discussing. Don't hesitate to lift verbiage from an article here and an article there. If you want to cite your source fine, but if you want to leave that out- I don't see any problem, as long as you're doing it in private correspondence."
"Another thing to keep in mind, is that you should be asking more questions than you answer. Asking a question takes a lot less time than writing an explanation. Don’t feel like you have to answer every single argument the other guy makes all at the same time. Narrow your discussion down to just one or two and deal with those before moving on to one or two others. If they ask a question that you don’t answer, and they ask it a second or third time, then just tell them you’ll get to that question once they answer this or that question that you asked which has gone unanswered by them."
Source: Apologetics for the Masses – Issue #77