These are the rules of The Flame. They do not attempt to teach how to flame, but rather define how the flame operates:
The flame is, at its core, the most basic method of establishing hierarchy in the internet community via aggressive means. While one can establish reputation through knowledge, humor or longevity, it is the flame which has the most potential to lower someone's worth or raise someone's standing among his or her peers.
Because the flame is used to develop standing in the community, only the community can determine if a flame was successful or not. One can throw out verbal barbs at another but, unless the community acknowledges the effectiveness of those barbs, they are fruitless and unsuccessful. One can never establish for him or herself that they successfully flamed someone -- if a flame has had impact, the community will acknowledge it in some form or fashion.
A failed flame is often worse than merely being a target. By getting flamed, you are a victim (perhaps deservingly). By unsuccessfully flaming someone, you prove yourself to be inept and comical. A valiant warrior who rushes at their opponent, trips and impales themself upon their own spear. Each flame so unsuccessful as to draw mockery from the community is worse than if you were flamed by another.
The flame requires some apptitude with the written word. Some successful flames are decisive strokes, some are subtle pricks. Some are wild flailings. But the skill of the word is paramount. The community has heard most of it before, unless you can dress your flames well, they will fail. Perhaps you can use intricate wordplay. Perhaps you can weave crude vulgarities into a shocking onslaught. But you must use something and use it well. People with no skill at the written word are recommended to sit silent.
Some flames will always fail. Their basis lies in misconceptions by the flamer that are not and were never shared by the community and so the community will always reject their worth. Flames about karma, post count, boasting about the flamer's real life and other such things will always be met with derision. The community rarely uses these measure to determine the worth of members in the community and so directing a flame at them will be fruitless.
Flames directed towards the community as a whole will always be absorbed and the flame will be considered a failure. The community itself is too large to be successfully flamed and, by definition, will not devalue itself as a whole.