During proofreading, writers look for any grammar and spelling problems not corrected during editing. Frequently, these errors involve misplaced punctuation, mispelled words or homonyms, or other errors that do not obviously create confusion about the meaning of what the writer has written. As a consequence, these kinds of errors can be difficult to spot because the eye glides over them. Proofreading, then, tends to be a painstaking task that requires the writer to review his or her writing slowly and carefully.
One method of proofreading that helps writers read their own work more slowly is to begin reading the draft one sentence at a time, beginning with the last sentence and working back to the first sentence. This method is effective because it forces the writer to look at the material apart from its "sense" since the sentences are now read out of sequence. This method is particularly useful for finding fragments, which might otherwise "blend in."
A second useful method of proofreading is to read the draft out loud, one word at a time. Sometimes it is useful to actually point to each word as it is read. Oftentimes writers mentally correct their writing as they read without even realizing they are doing so. For instance, notice that the following sentences can still be easily read despite the fact that the words are jumbled.
Sometimes it is useful for a writer to listen to a paper as someone else reads it. As the reader reads the draft, the writer can follow along with his or her own copy. If the reader stumbles or re-reads a section, this may indicate a place in the draft that needs clarified. Also, the reader may unknowingly "correct" or change the draft, alerting the writer to a potential problem. Watch, too, for places where the reader skips ahead or glosses over words or phrases.
When proofreading, writers should be especially sensitive to their signature errors, the kinds of errors they most frequently make. Learn to skim through a document looking for these personal faux pas.
Word processing programs come equipped with spelling and grammar checkers. These can alert a writer to typos, transpositions (switching one letter for another as in the scrambled paragraph above), spelling, and grammatical errors.
Finally, most people find it easier to proofread a printed copy of a draft rather than just reviewing an electronic copy of a draft.