NOTE: these rates are not set in stone and are only an average for this editor. The actual rate applicable to your document will depend on the depth of the edit, the quality of the writing, the topic matter, the proximity of the deadline, the length of the document and several other factors.
I have worked as a proofreader for over ten years. I began my proofreading career by proofreading translations of all kinds (technical, personal, documents, etc.). Later, I got a job working for a small publishing company. Among my duties, one of the most important was to edit and proofread articles and advertising copy.
Following my stint at the publishing company, I moved on to teaching ESL. I immediately saw a need for better teaching materials and began to work on various projects. My biggest project to date has been the development of a series of speech and pronunciation textbooks. I also revised and rewrote a number of other textbooks.
Overall, my experience as an ESL teacher (I spend a lot of time teaching writing and correcting students' writing), and my experience as a writer and proofreader make me a great candidate for your project!