I always think of a first draft of a story ( fiction or non-fiction) like a garden bed. I know that I want to dig deeper and find more of the story. One way to do this is to ask someone to read my first draft and ask questions. Just like empathetic listening and questioning, I ask for empathetic reading and questions.

This means that a reader isn't going to give suggestions or correct my writing and even tell me if he or she likes what I have written. 

He or she will simply ask the questions to help me dig deeper. When I consider the questions and answer them for my story's benefit, then I might dig a little deeper. 

I think of those questions like the tops of potato plants. They are green and leafy and when you grab one and pull it up, you'll find the potato. Sometimes the potato that comes up is big and fat, sometimes it's tiny. I find that questions are like that, too. Some questions are about specific details and to clarify something (like: what time of the day does this happen?). I think of these as small potato questions--because they can be answered pretty quickly. Then there are the big potato questions and they usually involve more thought and more writing. They also usually involve WHY or WHAT (Not always!)  For example, why did the girl want her father to move away? Or, what did the prince want most of all and why? 
Many of us are able to think of small potato questions--what color was her hair? What kind of house did they live in? Sometimes we have to think a little harder about questions that will pull up a big potato. Some people call these questions "open ended"  because the answer might go on and on. But, for our class, we'll call them big potato questions. 

Now, the other reason I ask a friend to read my first draft and ask questions is to see if I am being clear and to see if I have raised questions that will make my reader want to turn the page and find out the answer. So, if I get asked some big potato questions that I know will be answered later in the story, I can assume that I'm doing a good job with creating suspense. Remember, our reader will  be pulled along in a story by what he or she wants to find out.