One of the most humbling experiences a writer has is to see just how many errors creep into even the most carefully prepared manuscript. If you allow enough of them to pass on to the final version, you'll make quite an impression on your reader: a bad one. If you think you've purged your work of all the little flaws, if your computer's spellchecker comes up with nothing, don't be fooled. There are many, many more.

When

It's best to do your final proofreading about two months after you've finished the paper. That's the only way you can read each sentence from the proper distance. Obviously, you're not going to be able to do this. But you should let your work cool off for at least a week before you do the final hunt for gaffs, typos, and bytos. (A byto results from cutting and pasting into a sentence and leaving in words that don't fit in the new sentence.)

How

All finished? No more mistakes? Think again. The only way definitively to finish off every last error is this:

1. Make a copy of your paper.
2. Give it to a friend or spouse who's never read the paper.
3. Sit yourselves down at a large table facing each other.
4. You follow along as your friend or spouse slowly reads your paper, word by word (including the footnotes and the works cited list) out loud .
5. You, on the other hand, are not allowed to explain, justify, or rephrase. You simply mark the errors in your text -- and there will be errors.

There you have it.