This may seem a common sense concept, but let me discuss it anyway.
Writers do one important thing–they write. Okay, that's not the concept I'm talking about, but be patient.
I don't care whether you write in your local coffee shop, out in the park, or hole yourself up in your sanctum sanctorum for a specified period of time each day. You write. You create the plot, the characters, and the story.
However, you don't do it alone. You never see a writer pop out of his room after putting THE END on the manuscript and say to the world, "Look at me and the masterpiece I have created. All will now bow down and praise the work I have done."
I did that once and people laughed at me.
Okay, just kidding (or am I). My point is you have to rely on other people to finish your novel or short story. I know that's an obvious point, but sometimes authors tend to be a little selfish and defensive about their work. It's understandable and I've been there and, yes, walked away with a temporarily bruised ego.
I've written before about research. I love research. I enjoying visiting places and talking with people who are more knowledgeable than I about certain subjects. Most people, I've found, are more than willing to help. Yes, I have run into a few who aren't, who can't help me (even though I thought they should know some things), or outright won't. In those instances, I have to rely on the internet and reference books to help me with what I want to know. Or, I make it up (following rules, of course).
After I've written a story and edited it about a gazillion times (or so it seems), I can't subsequently start submitting it to publishers or agents. This is the nub of my gist. You need further help. You need to let someone else hear or read your work so that person can turn around and tell you it's crap. Yes, I said it, crap. Do you think Hemmingway and Margaret Mitchell and Stephen King wrote masterpieces first time out? No, they wrote crap. Then long after other people helped them, their stuff became legendary.
Writers' critique groups are one of the best ways to know you've written crap. Find a group who will listen to or read your work, give helpful suggestions, and even come up with brainstorming ideas to tweak your storyline. Unless you get some schmoe who can't stand the sight of your face, most critiques are about the writing. They'll let you know if something is exciting, boring, needs strengthening, needs more detail or less detail, if the characters stay true to themselves, or, as in the case with this sentence, you ramble on beyond your main point. And the best response you can make with these critiques? Shut up! Don't get defensive, don't whine and complain. Shut up, take the critiques in stride, and give some serious thought to them. Later, you can decide either to do something with the suggestion or decide the person who gave you the comment is dumber than a can of Spam.
Editing! Oh, my! I loathe editing. Now before my publisher and senior editor decide to boot me off their editing team, let me clarify. Editing MY work is tedious, exasperating, frustrating, and time consuming. This is especially true after I've gone through my manuscript umpteen times and still find stuff to improve. This is where you ask for help from others. Pay, trade, or barter with someone who will read through your novel and…tell you it's crap. No, seriously, who will correct the errors you've missed. There are professional editors who will do the job for a reasonable price. I also suggest picking up Todd Stone's book, Novelist Boot Camp, and review the section on what to look for each time you do a read through. It will help you and save time.
To get back to comforting my superiors, editing others' material is a wonderful thing. I'm not saying this to suck up. It's a learning experience. I see mistakes in what others write and learn what NOT to do with my own stories. This helps me be that much more diligent and creative with my writing.
One thing I need to express: writers need to know rules of grammar and punctuation. Do not submit anything until you are as near to 100% correct. Do not make your editor spend his/her valuable time correcting all but the fewest errors. I apologized to my Night Shadows editor because there was a problem with the version of the story she received. I take total responsibility for it and I will not allow it happen with Beta.
To sum up: Don't be afraid of critique and editing. Realize that what you have written is crap when it is crap and take steps to improve it.
Ask for help. You can't go it alone.