Do you just begin with an idea and then play and write as you go?
Do you accumulate screen shots, other material, and run through quite a bit of the game before posting?
I am leaning toward the second choice as this will afford a better decision on which characters to focus on as well as a better frame for the plot and character development.
If this were a full fictional story, I would have character notes, a story board, and piles of researched material before writing a single word.
Also -- how often do you go back to the beginning after having posted a bit and doing extensive rewrites?
(hey if this is not right for this forum space == local mods can do you thing with this,)