What qualifications do you need to become a proofreader?

In order to be a proofreader, you should be able to:

• Possess a working knowledge of the written language you're proofing
• Know which symbols are in use in the writing and which are correct, such as apostrophes, 'curly quotes', inch marks and feet marks, punctuation and its sequence and so forth
• Refer to a style guide from the publisher, which dictates such standards as capital letters mid-sentence, use of parenthesis and block quotes and other layout and printing conventions
• Determine the difference between two Words that sound alike, but which have different meanings, such as 'sale' and 'sail'
• Appreciate the 'voice' of the author, so that your grammatical corrections maintain that 'voice'
• Understand editorial marks, so that if you proofread on paper, the person who keys in your corrections understands exactly how to make the correction
• Leave a wide trail that represents your work, so that when it is double-checked (if it is) there is no question about the correction to be made.