Character, character, character — All story begins with and hinges on character. The reader roots for character, and the character(s) live the story, react to the setting, etc. It’s all about character.
In my own writing, it isn’t even my story. It’s the characters’ story. I’m the lucky guy who gets to check in on the characters now and then and write down what they’re doing and saying.
I actually check in with several of my characters each day. When I’m very lucky, I catch them at the beginning of a story and follow along as they act it out. And that becomes a new short story, novella or novel.
Description, description, description — Characters don’t exist in a vacuum.
Characters exist in a setting. Every one of them. And every scene exists in a setting.
Have you ever opened a story with dialogue? That’s fine. But is your dialogue happening against a white background? A void? No. Not in your mind it isn’t. Be sure what’s in your mind makes it to the page. As in…
What do the characters look like? How are they dressed [the parts the POV character can see]?
What’s around them? Are they in a room? Are they seated on a couch? Across from each other in chairs?
Is there a table between them? What’s in the background? Is it a dine-in table in a kitchen in a house (what’s it look/feel like per the POV character)? Is it one of many tables in a restaurant or café?
Does the waitress, waiter, child or other person passing through the scene seem brusque or harried or friendly or carefree? Are they attentive or dismissive? Bothersome? Annoyed or annoying? Etc.
Take Your Time. Describe the characters and the setting through the POV character’s senses and opinions (not YOUR senses and opinions) to give the scene life.