And then there is that other thing: when you think you are reading proof, whereas you are merely reading your own mind; your statement of the thing is full of holes & vacancies but you don't know it, because you are filling them from your mind as you go along. Sometimes -- but not often enough -- the printer's proof-reader saves you -- & offends you -- with this cold sign in the margin: (?) & you search the passage & find that the insulter is right -- it doesn't say what you thought it did: the gas-fixtures are there, but you didn't light the jets.
―Sam Clemens Letter to Sir Walter Besant, 22 Feb. 1898
“I was working on the proof of one of my poems all the morning, and took out a comma. In the afternoon I put it back again.”
― Oscar Wilde
Proofreading means examining your text carefully to find and correct typographical errors and mistakes in grammar, style, and spelling. Here are some tips.
Accurate proofreading and clear marking of corrections are indispensable requisites to the production quality of a book. Proofreading is the sole responsibility of the author. No one else will proofread the typeset text.
Proofreading is a prerequisite for effective written communication. The grammar and spellchecker in some software catches only some mistakes. To catch other less obvious errors you need to visually proofread your document. Get others involved. Asking a friend or a Writing Lab tutor to read your manuscript will let you get another perspective on your writing and a fresh reader will be able to help you catch mistakes that you might have overlooked
Work from a printout, not the computer screen. (But see below for computer functions that can help you find some kinds of mistakes.)
Read out loud. This is especially helpful for spotting run-on sentences, but you'll also hear other problems that you may not see when reading silently.
Use a blank sheet of paper to cover up the lines below the one you're reading. This technique keeps you from skipping ahead of possible mistakes.
Use the search function of the computer to find mistakes you're likely to make. Search for "it," for instance, if you confuse "its" and "it's;" for "-ing" if dangling modifiers are a problem; for opening parentheses or quote marks if you tend to leave out the closing ones.
If you tend to make many mistakes, check separately for each kind of error, moving from the most to the least important, and following whatever technique works best for you to identify that kind of mistake.
For instance, read through once (backwards, sentence by sentence) to check for fragments; read through again (forward) to be sure subjects and verbs agree, and again (perhaps using a computer search for "this," "it," and "they") to trace pronouns to antecedents.
End with a spelling check, using a computer spelling checker or reading backwards word by word.
But remember that a spelling checker won't catch mistakes with homonyms (e.g., "they're," "their," "there") or certain typos (like "he" for "the").