1. Make up your own facts. This is such a good strategy. In advertising it's called, "Data Free Research." Many people will believe whatever you tell them. Works for politics, why not discussions about photography?
2. Trot out algebra 2 and wiggle the numbers around ad infinitum. To the people who didn't make it through algebra 1 everything with an equation attached is scientific fact. Even the taste of a raspberry sno cone can be described and proven with a long enough stream of numbers and symbols.
3. Be the last one standing. Every time someone raises a question or disputes your data free research shout them down and keep repeating your "facts" until everyone gets tired of the whole circus and moves on to "which camera should I buy?"
4. Infer, imply or just go ahead and say it out loud: everyone who disagrees with you is a liar, a cheat or someone with a hidden agenda. I have a friend who describes all the other drivers on the road like this: "Everyone going faster than me is an asshole. Everyone going slower than me is a moron." It's the operative working methodology of forum rats as well.
5. Try to pick apart all the small parts of other people's arguments instead of concentrating on the big picture. This might consist of arguing about how fast a ship is really sinking instead of acknowledging that the ship is sinking. Or, that "it wasn't the bullet that killed him, it was the vascular damage and the subsequent loss of blood."
6. If challenged about why you are reinventing dirt, or why you insist on counting angels on the head of a pin, get very defensive and let them know that you are sharing your argument for the good of generations of future children as well as the miserable and intellectually downtrodden every where.
7. Graphs. Lots and lots of graphs. (See: data free research above).
8. If someone actually takes up the challenge and tests your idea, hypothesis, pipe dream, fantasy, terrible delusion, and finds it wanting in every way then immediately go on the defensive, protesting your brutal treatment at the hands of a reckless bully bent on derailing the train of intellectual progress.
9. Drink lots and lots of Red Bull so no one can outlast you in a thousand post grudge match. See point #3.
10. The best way to win an argument on the web is to shut down your computer, go for a walk, take a nice photograph and be secure in the knowledge that arguing on the web is addictive behavior and you just got yours under control. For now.