If a story itself is a sandwich, then conflict is the peanut butter and jelly to that sandwich. In other words, without conflict, your story is going to be bland and no one is going to want to devour it. As an author, you want your reader to say, "I couldn't put it down." How do you do that? With conflict and tension.
James Scott Bell said, "Conflict has long been recognized as the engine of story. Without conflict there is no drama. Without drama there is no interest. Without interest there is no reader. And no writing career." So what does it mean to insert drama into your story? Well, first you have to determine what your story is going to be about.
To put this in a nutshell, conflict is when your character wants something and can't have it. The details come into the why and how of that character being unable to get what they want. Once you have that basic idea, ask yourself the following questions: Is your story a man vs. man tale? A man vs. nature? Is the conflict external or internal?
Just keep in mind, that one side of the conflict has to involve someone or something that is sentient and conscious of their decisions. In other words, the character has to be able to make choices. A story about two tornadoes meeting in a field might be visually interesting; however, there's not much tension because nothing is at stake. However, throw a man trying to save his family from one of those tornadoes, and now we're talking.
These concepts may seem fairly basic, but you'd be surprised the amount how integral they are to your story. Without a clear grasp of the concepts, the rest of the story won't come together.
The next step, is to make this conflict familiar to the reader. As an author, you can make this happen by making protagonists that are likable/connectable, and to write conflict that has emotional familiarity. What do I mean by making a protagonist who is likable or connectable? It means the reader has to understand where they are coming from. Generally, most authors will write a main character who the readers will like. If not, the readers at least have to be able to connect or understand (empathize with) where the protagonist is coming from.
For example, let's say our main character is a person who kills others. For most readers, we aren't going to connect with that or like it. However, if we find out he's killing others to save his family, or his tribe, or his country, then it shines a different light on the matter. We can now get behind his actions and root for him. (This is a simple example and not fleshed out, but a common trope in books and movies.) After you establish that aspect of your protagonist, your next goal is to work in some emotional familiarity into the conflict.
Coming up next: Conflict Part 2--Emotional Familiarity.