You're not sure if you're going to write this in First Person, Present Tense; Third Person Omniscient, Past Tense; or Second Person, Present?
Worse, you're not certain if your protagonist is really the best character to tell the story of his/her adventure.
What to do, what to do?
1) NO HEAD-HOPPING: Promise yourself (and me) that no matter how many Points of View your story has, you will only change POV at scene breaks or chapter breaks. Repeat after me: I Will Not Head-Hop.
Say it again, aloud, "I Will Not Head-Hop."
2) Pick a Tense. Which is more natural for you, "I stumble to the loo," or "I stumbled to the loo."
Past Tense: Don't be surprised if the latter example flowed more easily. A lot of novels are written in the past tense. Some attribute that to our legacy of oral histories. It probably has more to do with our daily communication. When you tell your friends about the flasher you cold-cocked in the park, you tell that story in the past tense because it happened last night ... in the past.
Present Tense: There are stories that benefit from the author's extra effort of writing in present tense. For example, if you're writing a thriller or horror story and you need the audience to question whether or not the protagonist survives, present tense can help with that. Writing a Choose-Your-Adventure book? Then present tense works best since you are detailing "the now."
Immediacy is the key concept for deciding Present vs Past tense. If you need the reader to be right here, right now, right in this moment; then present tense is the way to go.
CAUTION: readers often find that escaping into a story written in present tense is more difficult (likely because it is a less natural story telling voice).
3) Pick a Perspective: First, Second, or Third Person. I, You, or He.
First Person: I snarfed the cookies.
Urban Fantasy relied heavily on First Person during its heyday, but like Present Tense, readers find it harder to fall into the story. First person also runs the risk of "I, I, I," -- which sounds like a kaiyaying dog. Oh hey, lookie there, I blogged about First Person Yipping before!
Second Person: You snarfed the cookies, dear reader, didn't you?
Unless you're writing epistolary novel (aka, Dear Diary) or this blog post, you can probably exclude Second Person. Yes, yes, there are exceptions.
Third Person: She snarfed the cookies.
Again, the most natural and therefore easiest of the perspectives to write and read. The tickle with Third Person is Omniscient versus Limited; Narrator versus Protagonist. Omniscient Third can see the Devil's Horde riding across the steppe toward our intrepid hero whoring in the village. Limited Third is the hero wholly focused on his bedbuddy.
4) Pick a Character (or Two or Three)
A story can be told from multiple characters' POV. As a guide, any characters I allow to tell the story have to be divergent parties who come together (either in love or in battle...or both) over the course of the story. In romance novels, there are typically two characters telling the story -- the two in the blossoming relationship. The two opposing parties who come together by the end of the story for the HEA. In Fantasy novels, these are characters who are after the same item/person/event but for different reasons with different paths and contrasting outcomes. The POV characters will naturally cross paths during the story; thus making it one cohesive story rather than three related short stories.
CAUTION: Too many POV characters prevent the reader from bonding with any of POV characters. So limit yourself.
The Final Test: If you can't decide which character, which tense, or which perspective here's a simple (albeit time-consuming) sure-fire test: Write Chapter One. Write it again from a different character's POV, different tense, and different perspective. Re-write as many times as you need to make the right decisions for the story you want to tell.
Dear readers, what tips do you have for deciding Tense, Perspective, and Character?