What exactly is a story? And what makes that story compelling?
Stories are interesting because they create questions in a reader's mind. You introduce an intriguing character, and the reader wonders about the rest of their existence.
What is going to happen to this character?
You create a dilemma for that character, which raises the question of "what will happen" to a higher level.
How are they going to solve this problem?
Your character goes on their quest (whatever it may be), and presumably trouble will follow them. They meet a love interest.
Are they going to end up together?
The villain shows his face.
How is this bad guy going to be exterminated?
The bad guy creates even more problems. The love interest is kidnapped in a scuffle!
How is the main character going to save their love interest?
The main character must finally face down the villain to save their love and the world.
Is this going to end happily?
The main character wins over the bad guy and it does end happily.
I feel sated. Is there going to be a sequel?
That's a very simplified version of a story, but should demonstrate how a narrative gives rise to a series of questions, and those questions are what keeps the reader reading. If those questions are not compelling, and do not directly address what's going on in the narrative, then you're going to lose a person's interest.
Go through your draft and pinpoint all of those story questions, such as "what's going to happen?", and "will the hero succeed?"
Are all of those questions answered?
For instance, if you read someone else's work and start wondering about why the main character is doing something (motive), or how the main character is able to do something (ability and sense), then you are straying from your key set of questions. Those questions should be answered in the narrative. If your reader ever wonders about something that is not explained, they will lose interest.
It is hard for a writer to read their own work and discover these questions, since they already know the story, but do pay attention to what others say about your work. If they are asking you questions about things that are not answered, you must find a way to answer them, or get rid of the scene where the questions arose.
If a critiquer is wondering about something that you never meant to address, that may be a clue that you are including something in the narrative that a) should not be there, or b) needs to be developed.
Answering questions is imperative to keeping a reader. If they do not feel answers coming at them in the beginning, middle, and end, or cannot see the answers heading their way, they are going to lose interest. Imagine what taking a test would be like without any problems to solve? The writer is leading their reader through that test, and the writer needs to explain all of the answers.