1. Let your writing rest for a few hours or days
The more distance you put between yourself and your writing, the easier it is to make improvements and find mistakes. When possible, let important writing sit for a few days. When you pick up the material again, it’s almost like proofing someone else’s work.
If you don’t have the luxury of letting your work sit for days, then a few hours will have to do. Find another activity that will help you distance yourself from the writing. You might want to take a jog, wash the dishes, take your dog to the park, or anything else that clears your mind. Ideally, you can approach the work from a fresh perspective.