1) Attack the age of your combatant. Usually fantasising that they are much younger than yourself makes it easier to swallow their differing opinions. If they think they are right it's immaturity, ignorance or naivety right?
2) Attack nationality ie if it's an Aussie they are always loud, arrogant and hypocritical. Make sure to include all three. They come as a set.
3) Attack their education. It's easier to be right when your opponent never graduated from the 5th grade?
4) Attack their expert knowledge. You are the holder of all knowledge remember. No exception!
5) Pretend they can't read properly. That's they only way they could possibly be disagreeing with you right?
6) Act righteous when they start to swear at you - I mean fancy someone getting frustrated just because you know more than they do???
7) Finally, If all of the above fails all you can do is drop and run. Send condescending private messages, put the idiots on your Ignore List or change your user name. You ALWAYS have the fact that you can act like a gutless turd and hide behind the pseudonym "TFan1156" or "ILoveMariasButt" and preach away to your hearts content because hell, at the end of the day, you don't have to face your opposition (who could very well be "BigHairyBikerHal") and tell him (or her!) to their face that they are wrong and you are, and always will be, right!