First, the story. Well, storytellers since Aristotle agree that every story has three main stages – a Beginning, Middle and End. Screenwriters call it a three-act formula: Set-up, Conflict and Resolution.
In the Set-up we are introduced to the Hero or the Protagonist. We see enough of him, his life and his surroundings to like him – to care what happens to him (or her). He wants something – even if it's only to carry on being happy.
Then he meets the Problem. This involves, or is, the antagonist – the baddie. He is a well-known character in films. Immediately we have Conflict. This is the longest act, with the hero solving an immediate problem, then finding another one in his path – in many cases it's the previous solution that causes the next stumbling block.
Eventually, though, he wins through. At least in Hollywood he does. We have resolution, and the protagonist achieves his goal.
That was an amazingly simple version of the three-act structure. But think about the last film you saw – chances are a hundred to one that it followed the formula. Here's another one:
HERO'S GOAL + OBSTACLE = CONFLICT.
That is the basis of good filmic storytelling. Conflict, conflict, and more conflict. The skill is to keep focus on the protagonist and to build conflict so the journey of the protagonist moves into more dangerous and challenging territory, leading to the final confrontation and resolution.
But let's get simpler than a Hollywood length feature and think about a non-fiction story. Well… non-fiction-ish! If you start photographing reality you usually find extreme boredom. So create fiction to represent reality. I think it was Sam Goldwyn who said, "Drama is life with the boring bits cut out."