Short answer: Your writing is ready for submission when you can’t possibly make it any better.
First things first, never send out your first draft. Ever.
When you catch an idea and ride it from start to finish, it can feel nothing short of exhilarating. Of course you want to share it as soon as possible! This is exactly why you shouldn’t.
When you’re still completely in love with new work, what you’re really experiencing is the residual thrill of writing. You need to wait until you can look at what you’ve written objectively and identify your own weaknesses.
If the thought of cutting a single word crushes you, by all means, keep your work close and enjoy it—just don’t submit it yet. If it hurts to edit yourself, you’re going to be in a world of pain when outside feedback comes in.
Put a piece of writing aside for a while, then go back for a second look. Look really closely. Pretend you’re seeing the work for the first time. Pretend it was written by your arch enemy. Be ruthless about what to keep and what to change. Then revise, revise, revise.
When you’re sure that you just can’t push your writing any further, get a second opinion from someone you trust. If you can find someone who isn’t your #1 fan, all the better. What you want is a thoughtful reader with a sharp mind and a keen eye who is willing to give you good, solid, constructive criticism.
Repeat the rest and revision process. Consider getting more feedback.
When you’re satisfied that the work is as good as it’s ever going to get and it’s something you would be happy enough to have in print or online for all eternity, then it’s time to bottle your nerve and submit.
It’s worth adding a caveat here that you will almost never feel 100% confident in any piece you send out. There’s usually going to be a gap between your artistic vision and what you ultimately produce. The goal is to take the work as far as you can. Then, just let it go.
— Nicole Melanson