Is it a western, a love story, a cop story, a coming of age story, science fiction, etc.?

Lines between genres can blur or become a combination of genres like say a horror-western. Mostly hybrids are rare.

Try to be clear about your core genre even if it's a hybrid.

Research the conventions in your core genre. See and study other movies like the one you're writing.

If it's a love story, know how that genre plays out. And what kind of love story is it? Rude, crude, sentimental, sleazy or slick?

Likewise if it's a war movie, detective movie, a teen movie, etc.

Knowing that will help clarify your story objectives.

Once you have the story objectives in mind, it will help you stay on track and not have to redo the whole darn script when you get to the end and discover it's not what you intended.

"Eighty per cent of success is showing up." —Woody Allen