A good document satisfies the following criteria:
Once I have received a document, I review it to determine how much work would be required to fully edit it and provide you with recommendations on how it can be improved. This will also enable me to provide you with a cost estimate for the job. If the overall cost estimate is acceptable to you, I shall go ahead with the edits.
I edit for overall comprehension, content, scientific accuracy, technical merit, citations and references checking, spelling, grammar, syntax and formatting, etc.
I use track changes within MS Word to suggest amendments, and insert clear, and often extensive, comments to identify areas that need attention.