That's what I do, not for spelling, but for typing the same word twice (my personal pitfall) and for substituting a better word to replace a dull word, if I can think of it at that moment.
Deciding on the story's plot and sort of establishing its ups and downs in my mind earlier helps, also.
Btw, I learned to think the entire story in my mind from Leger's earlier contest. This has helped me tremendously with other work.
No wonder, my hubby says I get that spaced-out look in my eyes, sometimes.