Comments are most welcome. Post your own self-editing checklist, or make suggestions to be added to the example below. Don't forget to check out the links---excellent online resources. And don't forget to go try your hand at editing on the Self-Editing Practical Application Page.

You don’t have to be a Mensa candidate or an English professor to self-edit your own work. There are many tools available to writers these days to help you pull your manuscript together and present a polished, professional document when submitting. Before we get into that, however, let’s talk for a few minutes about why self-editing your work is important.

Why Self-Edit

Self-editing is essential if you want to present a professional manuscript. Editors aren’t going to care that you’ve written the Next Greatest Novel Ever if they have to plod through a manuscript rife with mechanical, spelling or technical problems. You may have a wonderful story to tell, but if you haven’t taken the time to present it in the best light possible, your wonderful story won’t get the attention it deserves. It’s true that first impressions are lasting impressions, so your ultimate goal is to make a good impression.

How To Self-Edit

The first line of defense is built right into your word program. Everyone has a spell check and a grammar check. These are quick and easy to use.
Make yourself a checklist that consists of items you know you personally need to address in your work, as well as the more usual items. See the example below.
1. Spelling. Check for those pesky words that are words, but not the right words.
2. Capitalization
3. Punctuation
"I'll eat later," Mom said. --notice the comma.
"I'll eat later." Mom dashed out the door. --PERIOD, because the tag is an action, not a dialogue tag like said, ask...etc.
4. All paragraphs are indented properly.
5. You’ve followed the format set forth in the guidelines of the house you’re querying.
6. Active Voice: Do a search for the verbs was/were and had/have. If there is an -ing verb following, delete the was/were and conjugate your verb to -ed. Double check your "had" formations, so you don't overuse those in a flashback type situation. As you read your manuscript the final time, make sure you've used strong verbs whenever possible and shows the action being performed rather than the action happening to someone or something. Be sure you SHOW more than you tell.
7. POV: remember that if the POV character can't see it, you can't describe it. This includes the POV character's eyes and facial expression. Watch out for omniscient POV. This is where you're in the POV of all the characters, main and secondary alike. This is unnecessary, and makes it difficult for the reader to connect with "The Stars of the Show"--your hero and heroine.
8. Check for repetitive words and phrases.
9. Strong, vivid verbs. Did you use the best verb you could? Did you feel the need to qualify it with an adverb?
10. Adverbs. Look for -ly clusters.
11. Balance. Is your narrative, exposition and action well-balanced?
12. Did you tie up all the loose ends?

The best thing you can do as a writer is to continue to learn about the craft, and grow from the knowledge you gain. If you aren’t teachable; if you don’t take what you’ve learned and apply it— you are doing yourself a great disservice. Find yourself a good, honest critique partner. Not someone who’s going to blow smoke up your skirt, but someone who will tell you the truth about what you’ve written. You won’t benefit from a crit partner who only tells you how wonderful you are. Grow a thick skin. Rejections hurt, so wouldn’t you rather hear it from a cp than an editor? There are so many resources for writers out there on the internet; so many articles written by authors for authors. Links are provided below.

Barbara Dawson Smith’s Self-Editing Checklist: http://www.barbaradawsonsmith.com/selfedit.html

Self-Editing by Stephanie Bond: "Self-Editing Checklist Series." http://www.stephaniebond.com/writers'_articles.htm)

Self-Editing Practical Application Page

Characterization
Characterization Practical Application Page

Writing Techniques
Writing Techniques Practical Application Page