I have several years of experience copyediting and proofreading many different types of writing, including web content, scholarly articles, advertising copy, and personal documents.

Copyediting and proofreading are often used interchangeably, but they are different skills. A copyeditor will not only correct errors of grammar and spelling but will ensure consistency of style. If you have a preferred style guide, your copyeditor will see that your project conforms to that style guide; if not, your copyeditor will ensure that your writing is consistent with itself. 

Your copyeditor will also suggest ways of refining your prose. A sentence can be cumbersome without being ungrammatical; a word can be inappropriate without being wrong. Suggesting ways of improving the clarity, conciseness, and tone of your writing is part of a copyeditor's mandate.

Additionally, copyeditors often perform basic fact checking. Your copyeditor might not have expert-level knowledge of your subject, but he or she will check dates, figures, and names to ensure they are all correct.

In my capacity as a copyeditor, I have worked on scholarly articles, advertising copy, and web content and blog posts covering a variety of topics. I am familiar with all the major style guides, including APA, Chicago, and MLA.

Proofreaders, like copyeditors, will also check your grammar and spelling. For this reason, it's best if your proofreader and copyeditor are different people. If your copyeditor misses something (nobody's perfect), then a new set of eyes is more likely to catch the error than someone already familiar with the text.

In traditional book publishing, proofreading comes after the book is designed. For this reason, the proofreader is responsible for catching errors that were introduced in the design process. These include typos, incorrect page numbers in the table of contents and index, and problems with formatting (e.g., awkward page breaks, misaligned text, poor spacing between words). Many of these skills transfer to electronic media. You won't find page numbers on many websites, but a proofreader will still check your hyperlinks.

As a proofreader, I have worked on PowerPoint presentations, website landing pages, and résumés