Read the work through once for content. This will familiarize you with the work so when you edit, you can focus on things such as grammar and punctuation.
Read the work and mark content changes. These include grammar problems, sentences that need to be reworded, and inconsistencies. Looking for errors in only the content during this reading will keep your focus on the content instead of having your attention divided between content and technical changes.
Read the work and mark technical changes. These include punctuation and spelling. This may also include formatting for writing styles such as those of The Associated Press or Modern Language Association.
Read the work through one more time to make sure you haven't missed anything. Mark any final changes that need to be made before you give the work back to the writer to revise.
Take a day away from the work, if possible. If you read the work immediately after you write it, you may not read it as critically as you should since you are so close to the work. Taking a day away from it will give you a little distance from your work and let you approach your editing with fresh eyes.
Know your weaknesses. Some writers are poor spellers and others struggle with proper punctuation or grammar. If you know what mistakes you frequently make, you can watch for them in your writing.
Read through the work and mark changes to the content. This includes sentence structure, grammar and other wording problems.
Read through the work a second time to mark technical changes such as punctuation, style, formatting and spelling.
Read the work one more time to make sure you haven't missed any errors. Mark anything else you notice that needs to be changed, and you're ready to start revising.