There are so many guidelines it's hard to know where to begin with such a generalized question.
First, you have to write what trade publishers are buying. That means your work has to have its word count fall within the acceptable range for its genre--fantasy is far longer than horror, for instance. Its content has to suit its genre and be right for the most likely readership. It can be similar to something already published and popular, but not too similar and not at all derivative.
To meet those criteria, you need to be well-read in your genre's current offerings.
Next up is whether your characters and story are interesting to potential readers. If they're not, nothing you could do will make that manuscript publishable.
Assuming your story and its people are fascinating, now you get to the nuts and bolts of the writing itself. Your manuscript needs to be virtually error-free. Yes, we all make typos, but if you use the wrong word or can't punctuate and capitalize dialog and its tags correctly, count on rejection. Besides no mistakes, the writing itself needs to be good, the character development rich, the pacing right, the story unpredictable yet plausible.
Achieving all this isn't something that happens very often on your first novel. Most of us wrote a million original words, which took about 10,000 hours, and got feedback, took classes, and otherwise upped our skills before we produced anything publishers wanted to see.