For the past two years I have been proofreading for two Polish companies devoted to teaching English as a foreign language. The main aims of those jobs are to make the writing flow as though it was written by a native speaker. I am an English teacher by trade so I am also aware of the various grammar rules to be followed. I've also worked in advertising and marketing as a copywriter for five years in the past so I'm familiar with the writing process and how painful it can be to have someone fiddle with your work too much.