How do you find the best academic editor or proofreader to work on your essay, thesis or dissertation? Word of mouth is a good tactic; ask other people on your course if they have used anyone. Your tutors, lecturers and course leaders might also know of someone. Enterprising freelancers often leave their flyers and business cards strategically located around campus, so look out for advertisements on noticeboards and in pigeonholes.
However, just because someone has advertised doesn't necessarily mean they are any good, of course. Most reputable freelance editors will give you a rough idea of how long your essay should take them, and give you a guideline as to price. Many freelancers charge by the hour, or work by a set fee per one thousand words. Often they will be happy to proofread a sample section of your essay or research to give you a taste of what they can do.
Don't just go for the cheapest option: there are plenty of essay factories available on the internet, and really, cheapest is not going to be best. Go for someone who works as a sole operator rather than using a company. They will have the time to give full attention to your essay, and they have a professional reputation to maintain, so they will do their best for you.