It is better not to try to write and proofread at the same time.
Writing is creative, proofreading analytical.
If you try to do both at once, you won't do either one well. Remember that proofreading isn't reading. If you read for meaning, you can't concentrate on the details, and proofreading is detail work. Reading out loud is slower, so you'll have more time to notice details. Read the paper from back to front, looking at each sentence as an isolated unit.