|IT CAN BE DONE!|
From the start, you've gotta keep your cool. Let them trash talk you, scream bloody murder at you, use every word in the book that their mother forbid. Don't fire back, at least not in the same way they did. This is key for your... umm... "Discussion" with them.
Find out what they're actually mad about, what set them off. With most traditional trolls, it's really nothing. They live to instigate and just yell at other folks to elevate their empty ego. Respond with logic... they don't know how to handle it. Keep a cool head about it and it ends up dumping cold water on their plans. They usually give up after awhile. It's the "imbalance" in the reaction that throws them off. Baseless accusations don't hold up well against well-defined thought. Here's an example.
"AirsoftKid1997: OMG YOU PLEY WITH NERF YOUR A DUMB@$$ HAHAHAHA"
"AntiTroll Champion: Yeah! It's a lot of fun and all my friends from school play too."
Instantly you've established A: you can spell, B: you have friends, and C: you haven't freaked out. Trolls thrive off the reactions they're looking for. Deny them that chance.
"AirsoftKid1997: LOL YOUR A BUNCHOF WUSSE GIRLS HAHAHA"
"AntiTroll Champion: The girls that play Nerf with us are pretty tough, actually."
Now not only have you established that his taunts aren't getting to you, but that you can actually partake in activities with girls, something he won't have for a few more years or so at this rate. You've managed to insult him, but not directly.
"AirsoftKid1997: YOUR A DAM STUPID NERF HERDER YOU F***ING @$$!!!"
Go in for the kill
"AntiTroll Champion: Are you using profanity because you think you're cool? Or do you simply lack the vocabulary to come up with a substantial response that will elevate your position? Either way, folks like you just make me laugh. If that's your goal, then by all means, please continue."
Aaaand those are the big guns. I just love hitting trolls with a big heaping dose of grammar/spelling correct demeaning comments. You've burned his intentions to the ground and, if anything, you're probably having fun watching him make a complete fool of himself. Sometimes it takes longer for a troll to give up on you, in which case, the option to completely ignore them is also quite satisfying.
Lets say you're in a chatroom. This is the best place to ignore a troll, as you can continue to talk with other folks there as if he's not even there. Eventually they fizzle out and give up.
There's still the rare instance that you can TURN a troll, or TRANSFORM them. This happened to me yesterday using the steps provided above. He went from yelling about nothing through comments on the Elite Range Battle 2 video to actually explaining why he was upset. I never really fired back at him and eventually, using logic, I exposed his useless attempts to troll and revealed that he should've just asked a question I could've answered. Approaching trolls with a cool head is the best chance to actually turn things around and get to the core of their issue... but that's only if they have one. True Trolls who are just trying to pump their ego won't have any other logical underlying reason. It's the ones that you can reach that you can "transform" back into normal people with a little prying.