First, I write something. Anything. Usually it's in reaction to something, or perhaps I just sat down that day and free thought together something. Usually both! It will be hilariously incoherent and disjointed and misspelled.
After writing the foundation, I let it sit there and simmer. It depends on a few factors the speed with which I publish. Is the post long and hard to format (posts like "Journey of the Nunchuck", while entertaining and full of pictures, are a pain to format properly without it falling apart) ? Is the post still relevant (a post on copybot today would be way way WAY behind the times, and sometimes what seems like a big deal today really isn't tomorrow)? Can I merge it with something else? Usually I do the latter. I throw it all into a giant pot and stir.
After stirring for a bit, I look in and see if I have something edible. Sixty percent of the time I don't and I throw it down the garbage disposal. Forty percent of the time I might have something worth reading and relevant!
Then I run it through my two best friends: The dictionary and spellchecker. With regards to grammar, I usually pray I don't have fragments and that I have more than two sentences per paragraph. Sometimes despite that things slip through, though, so I read my own posts seven times. After that, I let it languish in draft stage while I do more relevant things like watch TV, play SL, or watch paint dry on cinderblock.
Finally, months (or decades, depending) later, I publish the post. Sometimes if the draft has been delayed long enough, it won't show up on top, but instead Blogger will slip it in somewhere else date wise. So if it appears that I haven't updated, I probably did but Blogger buried it in the archives.
And then you read it and in fact you're reading it right now. If you are reading this sentenec and there is no grammatical errors, I consider myself a success. Now if you'll excuse me, I have to pat myself on the back some more. I might be back in time for my daily self-worship.