This stage is where you polish your work. You check for grammar, spelling, punctuation, citation, and writing conventions.
You will develop your own checklist as you go which addresses the errors and issues you personally need to address in your own writing - but can use the revision checklist as a start.
It is an excellent idea to have someone else (or as many people as possible) read your piece of writing at this stage to check as well! Another tip is to have them read your work aloud to you. We tend to "fix" errors in our own writing as we read it and sometimes do not notice the little things. When you hear your work read by someone else, these issues can be often heard.