It is amazing how many new writers think that once they have placed the words to paper that the process is done and now is the time to send it off the publisher. They are so wrong. There are several steps to the writing of a novel: Creation, Continuity, Creativity, Reality, Finality.
You wrote the novel. That was the creative process. You created a manuscript. It is now a tangible item but it is in its purest, raw form. That manuscript is in no way ready for publication. In fact, it really isn't even ready to be presented to anyone!
Your document - within the realms of your own mind - is the most fantastic, well-written, next best-seller... or at least you think it is. Trust me, it isn't.
Now is the time to go back through the story and look at your plots and sub-plots. Did you satisfactorily tie-up the loose ends on each of them? Or are there dangling issues that need to be addressed? Having Jack find that 800 caret diamond in the cave is a stroke of pure luck. So what purpose did it serve? Why an 800 caret diamond? Other than Jack sticking it in his pocket, what happened? Or how about Julie who thinks Stanley, the president of the chess club, is a cute boy. Did Stanley die? Did they date?
There has to be a reason for everything (so I've been told) and if you mentioned something, you should resolve it.
Jack used the diamond to cut through a giant 3 inch glass wall. When it shattered after being scratched by the diamond, a shard hit his hand and he dropped the diamond and it was lost. As for Stanley, our heroine thinks he is dreamy but discovers Stanley is gay.
So once you're done writing, you go back through the work to make sure all the loose ends are finalized. But, you're not done. As you go through the work you realize that for Jack, the shattering glass crumbled the thin cave floor and he fell into a larger cavern below.
Ah-ha! You've hit upon Creativity. As you go through fixing things you discover new opportunities, twists and turns for the story to make it even more robust and thrilling.
Finally you come to realize that at some point you need to face facts. Reality. It has three faces. Face 1: The sheer size of Jack's diamond would make it difficult to carry in a pocket. Or Julie's infatuation with Stanley could actually be better for the story, so Stanley is no longer gay. That is part of the reality. Face 2: You now know that somebody else needs to read this work. In other words, you are looking for edits. So you have your mom, your friends, you neighbors and maybe even your local writing group buddies take a crack at making sure the story is good, the spelling is correct and everything is falling into place properly. Face 3: You need a real editor, somebody who knows what they are doing to address the writing itself.
Now you are approaching Finality. The last stage of editing. This is where you receive back a heavily marked and scribbled upon document, totally destroying your psyche. Are you truly a writer?
Editing is a process that can take several weeks to several months. Editing isn't just making sure that the words are spelled correctly or that the punctuation has been properly assigned. Editing is looking at the document and evaluating the contents, validating the POV, verifying plots, subplots and storyline for continuity. Editing is a process that you can do up to a point.
At some point, whether you want to believe it or not, you will need to have another person edit your work. This should be somebody who is not familiar with your current work so any surprises, plots, etc are properly addressed.
As the author, you are too close to the work. In your head you know all the details and if one is missing in the text, it is in your mind's eye and therefore, must also be in the tale. Or you may have deleted a scene that revealed the size of the diamond and to say it was too large later seems to come in from nowhere, the blind side, per se.
Bottom line. Never ever submit in a raw work.