Book openings are hard.By this I don't mean breaking in a thick paperback or turning on the Kindle app.
Opening with the hero dangling from a window ledge makes for a great mental image, but what then? Once he saves himself, it's hard to top that action. So you want to open with action, but not too much action.
Definitely do not open with," It was a dark and stormy night." Setting should color the action.
Is it best to open in the protagonist's POV? You need to introduce the protagonist, reveal his initial need / goal. Hint, if not show, who or what opposes her? Whom can s/he count on for help?
The reader needs to be (get) hooked.
I cut chapters from my WIP's opening. Then paragraphs. I'm still trimming words. Striving for that just-right opening that entices a reader to keep turning the pages. To read the opening and say, "I want to buy this book."
What do you think makes a perfect story opening?