When it comes to narration, there are several choices to make based on what tone you’d like for your book. The one people tend to most talk about is if the narrator speaks in first or third person, but with present tense becoming more popular, Narrative Tense is becoming a hot topic.
For the most part, past tense has been the standard in story telling (“She walked down the street and looked around). With the popularity of present tense novels like The Hunger Games, however, the present tense is becoming more common (if not yet the standard). There are plenty of pros and cons to writing in either (some people find present tense more engaging, others find it distracting…) but the main writing rule when it comes to narrative voice is to be consistent.
One more than one occasion, I have been asked what to do in past tense narratives for facts that are still true after the telling of the story. For example:
My sister was named Sally.
Unless Sally is now dead, she is very possibly still named Sally. Wouldn’t you then want to say, “My sister is named Sally”?
Not unless you have a present tense framing device.
For, you see, the fact that you are using past tense in a story doesn’t mean that everything written is only true in the past. It is simply the narrative tense you are using to tell your story. As a coworker of mine once described it, “If I were describing my trip ten years ago to Germany, I might say, ‘It was beautiful. There were all these tiny streets and medieval buildings.’ It’s likely it’s still beautiful with tiny streets and medieval buildings. I just happen to be describing what it was like in the moment I was there. That is my narrative tense.”
Similarly, unless you have a present tense narrator who is covering things in the past as a clear framing device (“I didn’t know it at the time, but…”) it is important to stay in a consistent narrative voice, even if that means you’re saying “John was a tall man” when John might still be a tall man after the story.
Similarly with present tense, everything in the story should be in present tense, unless you are actually describing something happening in the past (these would be sections that would be in past perfect in a past tense novel). For example:
In present tense:
I walk down the street, looking at the spot Jack and I went on our first date.
“I walk” is in present tense, meaning everything happening in-story should be in present tense (e.g. you shouldn’t have something like “I walk into the building and looked around” but “I walk into the building and look around”) but as the narrator and Jack’s first date happened in the past, that verb is properly in past tense.
In past tense:
I walked down the street, looking and the spot Jack and I had gone on our first date.
Here, the narrative is already in past tense (“I walked”) meaning everything happening in-story is related in past tense. To show something happening before the story, you then switch to past perfect (“had gone”).
Once you have decided the narrative voice of your story, you should stay consistent in either using present for in-story and past for the past, or past for in-story (including things that remain true after the story) and past perfect for the past. Slipping between tenses once one has been established can at best be jarring, and worst look like sloppy writing.