There is, unfortunately, an audience for this sort of advice ... or at least ought to be. I've heard only a few of these points ... and I thought I'd heard it all:

Unsound sticks, or, Arguments Catholics Shouldn't Use - Pugio Fidei, via TMH @ BHT.

A couple of these have entered my mind, that is, I've been tempted by these considerations and have, on occasion, expressed them. They've gotten the better of me.

Like this one which is argued in Currie's book, the tendency to pit Jesus against Paul:

12. Do not descend into arguments over whether we should give priority to Jesus or St. Paul as our teacher of the doctrine of justification. Granted, some Protestants err in claiming that Jesus left it to St. Paul to teach the Church the theology of salvation. However, it is no sound rebuttal, but simply the photographic negative of the Protestant error, to boast that Catholics give primacy to the Gospels.

Currie actually goes on the draw a parallel with Marcion which is certainly out of bounds. However, undeniably, it results in a lopsided message.

Now, this one is difficult because there are errors of history in the Bible:

10. Never compromise biblical inerrancy in order to score points against Protestantism. For instance, Protestants will often allege that the books of Maccabees cannot be inspired Scripture because they contain contradictory accounts of the death of Antiochus Epiphanes. And unfortunately, sometimes Catholics, instead of defending the books of Maccabees by harmonizing their data, will retort that by that standard the books of Samuel and Chronicles cannot be inspired Scripture either since they contain contradictory accounts of the death of Saul. This defense is thoroughly inadmissible: it invalidates the authentic Catholic standard regarding the necessary characteristics of Scripture (one of which is inerrancy) just as well as Protestant standard.

And how Judas died. Obviously, the presence of textual inconsistencies is no reason to reject a work as a part of sacred Scripture.

I've had 2 Peter 1:20-21 quoted to me which, I guess, is arguing for the inspiration of Scripture? Fine, but right before that [vss. 16-19] is an appeal to accept apostolic teaching as genuine, based on first-hand testimony, presumably against others whose teaching wasn't so grounded in historical fact and personal experience.

17. Never ask, if a Protestant believes his salvation is eternally secure, what motivation he has to do good and avoid evil. The answer is obvious (and embarrassing to the Catholic who asked the question): the love of God.

We step in it all the time because, truth be told, we don't care how we come across. This isn't about us at all. That's where we are wrong, because our dialogue partner is sensitive, looking for clues to our integrity, reading our character as a testimony. We're already on thin ice simply by asking questions, challenging assumptions and suggesting alternatives. Breach any of these and there's no second chance. It's alot easier to dismiss you once you do. Yeah, I know it's tough, but they make the rules that you're just supposed to know.

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This sort of ties in with this America article:

For as the council declared, “The bonds which unite the faithful are mightier than anything which divides them” (“Pastoral Constitution on the Church in the Modern World,” No. 92).

But I think the article overall exaggerates the problem.