I think this can be useful: Eight Ways to Win an Argument, by Schopenhauer. It’s a resume of the book The Art of Always Being Right, but I think that buy the book and read all of it still a better option, but that is ok for now. One of the tips:
Hide your conclusion from your opponent until the end.
Mingle your premises here and there in your talk.
Get your opponent to agree to them in no definite order.
By this circuitous route you conceal your goal until you have reached all the admissions necessary to reach your goal.
But for trolls you need some different techniques, so read Trolling lore. If you never had a problem with a troll or never saw a comment of one of these annoying people, or you are very new on web or you are the luckiest person I know. (via Lifehacker)