1. Give yourself extra time
It can be hard to do when the due date is coming, but allow for time between a rough and a final draft. You will tend to see mistakes more easily if you do this. Time distances you from what you think you wrote and lets you see what you actually wrote, allowing you to better see what needs to change and be corrected.
2. Read the essay twice
Read what you have written once from the computer and once from a printed copy. In reading the essay twice, you may see mistakes the second time that you did not see before. You can also often see mistakes when you read from a printed copy that you don’t see when you are reading from a screen.
3. Read it aloud
You will hear errors that you might not see when you are reading silently. This can be especially useful for hearing mistakes like repeated, redundant words or phrases, things you might want to take out, and unclear, awkward or run-on sentences. It can also be really helpful to read a paper aloud to someone else. When there is an audience, your ear will scrutinize the essay more, and you will see more things that should be corrected.
With this approach, proofreading is not about the many grammar rules. It is meant to develop an ear for writing, to have you put more energy into revising a paper, and to allow you to see mistakes by reviewing what you have written. You will better hear what needs improvement and clarification by examining the paper several times from different angles. The improvement in a paper can far outweigh the effort of accomplishing these simple steps.