When your only editor is you, you need to judge it twice as harshly. Leah McClellan provides ten quick but insightful tips to clean up your work before others claw into it.
Save proofreading for the very end, after you are happy with everything else, in order to avoid rework. Remove any potential distractions. Analyze sentence by sentence to really hone in on words, grammar, and punctuation, and read them out loud or backwards. Maybe make different passes at a document based on hunting for different sorts of mistakes. Make a note of anything you are unsure of and look up the solution later. Likewise, do your fact checking and checking of other elements (like tables) separately. If you make any last-second phrasing changes, reread the sentence and probably even the paragraph to ensure everything still reads properly. You will probably get familiar with the mistakes you make most often, and when you are, they will be easier to correct. If you ever notice your attention drifting on a given section, read that section over. And at the very, very end, check your formatting—paragraph spacing, indentations, etc. Then your writing will be perfect, maybe.
You can read the full article here: http://writetodone.com/get-your-eagle-eye-on-10-tips-for-proofreading-your-own-work/