Movies and books are different mediums. With a skillfully engineered scene, a movie director can deliver enormous amounts of information in seconds; a 30 second chase scene tells us all we need to know about good guy & bad guy & setting & time period & character. We don't need their names or a single word of dialogue; their emotions are on their faces and in their body language, including when the villain succeeds and the hero fails. The average reader consumes 200 wpm, 100 words in 30 seconds. Less than half a page, 2 or 3 paragraphs, and you simply cannot do the same job as film inside the reader's window of "I don't care anymore."
So rule 1: Do not open with a high-stakes action sequence; readers will not care because they don't care about the characters, and you can't write a high-stakes battle or pursuit and get across enough information to make them care in the opening. They don't know who to root for; unlike the movie where a skillful director can show them who to root for in the first second.
Elsewhere, BG information can be delivered by direct internal contemplation (thoughts, memories), indirect contemplation (she recognized him, the weatherman from channel 7, the only reason her mother watches the weather) direct dialogue (me telling you about my past, or a story from my past that reveals something about my character), indirect dialogue (my sibling or lifelong friend or parent telling you about my past), or things like detection and inference (reading my diary, seeing an old home movie or photographs with me in it). Or flashback, though I never use that mechanism.
Those are mechanisms. They can stray into info-dump, but the way to prevent that is to be stingy with background information, and deliver only what is immediately relevant to the reader and character; only reveal, through some mechanism, what the reader (or another character) needs to know to clarify this character, her emotions and actions. Dole out background and don't be in a rush to deliver it.
Just like with new acquaintances IRL. We can meet somebody new, in the office or school or on a flight somewhere, and feel something on the spectrum from "dislike" to "indifference" to "like" without knowing anything about their background. One harsh line to a child may be all it takes; one tasteless joke or even expression or lingering glance resting on a woman's breasts. We don't need to know this guy's life story to know he is a lecherous old jerk.
The same with characters, for readers. Don't aim to get us invested in your character all at once. Give us one important point through one of the above mechanisms, a few dozen words, then refrain; dole it out to us in pieces small enough to swallow without choking on it.
This does not really demand much planning on the part of the author, as the story progresses opportunities to express "character" will appear. Elements of the character are expressed then, when they matter to the story; when they have consequences in how this fictional character reacts, decides, chooses, etc. As an author, keep your eyes open to constantly creating tiny conflicts, which help reveal character. Mary arrives at the pasticciere half an hour late, all that is left is a lemon danish, and a blueberry one. She usually buys one apple turnover. Which does she buy? The lemon? The blueberry? Both, in case she doesn't like one of them? Neither? Is it a firm choice; definitely lemon? or she hates lemon? Maybe she decides Screw fruit! I'm having chocolates for breakfast, it's all sugar anyway.
Reveal what is necessary for the reader to know about your character, as they need to know it. If you have a good story, those details will be crucial to how the story turns out, who she is will guide her actions and decisions and be crucial to the turning points in the plot, so there will be plenty of opportunities to show the background as you go, a hundred words or so at a time.
