Past and Present Narrative - What Happened versus What's Happening

Just some quick examples of how the narrative present varies from the narrative past.

Writing the Narrative Present: Immediacy in Action
Narrative Present involves reporting events that are in-progress, story-wise.  They can be written in the present tense or the past tense.

Present Tense: I'm running when I trip on the walkway.  Damn.  This isn't going well.  First the windshield wiper, and now I'm lying on my belly on the concrete.  And those goons are still after me.

Note the immediacy here - we feel the strain on this character.  But there isn't much room for perspective.  Who's this character running away from?  What the heck is up with the windshield wiper?  Past tense offers a bit more remove from the events of the story, thus providing more space for context details.

I tripped on the doorway.  I held my breath.  It wasn't going well.  If the windshield wiper hadn't broken, I wouldn't have been running in the first place.  I would have been warm and comfortable in the car.  But I didn't have time to worry about that.  I needed to get away from those goons.

Narrative Past: Adding Context (and Memories) to Your Fiction
With the past tense, our character was able to give some context to the details of running away.  But to really know what's going on, we need to mix in some narrative past.  I recommend writing the narrative present using the past tense because of the added context above - this means we need the past perfect tense to offset our narrative past.

The windshield wiper had snapped in half, shattering the windshield at just the wrong time.  And I was on foot when I needed to be putting some real distance between me and those goons.  Yeah, not a good day.  I turned a corner.  I spotted a doorway - it looked like escape.  I shoved open the door, but then I tripped.  Yeah - just when I thought the day couldn't get any worse.  But then I looked up.  Yeah, things were about to get a lot worse.