I type very fast (as fast as I can talk), but I still make errors. One thing I use that`s helped a whole lot is "Smart Typing Assistant"
(for Windows). It takes very little resources, sits in memory, and I
can customize it to correct words I usually mis-type. That being said,
I still go back and re-read it, trying to correct spelling errors. So I
end up editing pretty much each post...simply because I want to "save"
it before I edit it.