These are great tips about dialogue.
The note at the end is definitely very important as well. The thing about writing advice I'd like everyone to remember is that it's meant to be used alongside the learning process, not as hard and fast rules that will automatically turn you into one of the historical greats. Also, different things apply to different areas. Stories are, ideally, living things that breathe and move organically in ways which do NOT play well with rigid ideas like the template approach I see too many people try to use because they think there's some kind of algorithm or recipe for writing like it's a hard science when it really isn't.
These things are GUIDELINES. And unfortunately, the only way you'll get them to work properly for you is by treating them as such and applying them loosely so you can see the difference, understand why they're like that, and then adapt it properly into your lexicon so you can organically utilise them as developing skills on every new project exactly where and when and how they're needed.
If I can add on: I cannot recommend learning stagecraft enough. Go to your local drama class if there is one and hopefully they'll still remember all these things and with any luck it won't have been left to rot while they adopt the capitalist cookie-cutter spoon-feeding audiences-are-stupid-and-need-everything-spelled-out-for-them-because-we-killed-media-literacy bullcrap we see in too many shows and films nowadays. I'm still learning these skills myself though I personally didn't learn them from reading a post like this. I learned them through observing the dialogue in existing well-written shows, film, and printed scripts, alongside performing them on stage to be taught and experience how to get it all working smoothly.
Also, to expand upon points 2 and 11 from my perspective:
I like to imagine we are peeking through a window into the characters' worlds.
They won't and should never be saying anything for the audience's benefit because we don't exist.
Now obviously at the meta level the whole show is in fact for the audience, but the main point I'm getting at is that - in my very strong (very sure I'm objectively correct lol) opinion - your characters should never feel or look or otherwise come across like they're mouthpieces for the writers to tell you information. The characters shouldn't act like they're having a scene to tell you shit even when they literally are, because within the world of the story they aren't. So the dialogue should reflect that.
Ask yourself one simple question:
Would this character say this thing, to themselves or to another character or whatever, if we weren't here on the other side of the screen to hear it?
This is, in my opinion, the biggest and most painful mistake new/inexperienced/underpaid/rushed writers make.
If a character/group of characters wouldn't need to explain it for someone within the world of their story, then they wouldn't explain it. **
And in those situations, you as the writer just have to learn visual storytelling, good editing skills, other types of clue-leaving in how you write natural interactions which ignore the audience's presence, and expect/trust the audience to have enough media literacy skills to put it all together into understanding what's going on without being spoon-fed like they're too busy watching tiktok or something to pay attention to the story. (And if they are, then they can put the phone down and pay attention or put the story down and stop wasting their own time barely half-engaging with something they clearly don't care enough about to engage with properly anyway.* People don't learn if they're never expected to.)
But that's a very complex skill which takes a lot of time and experience to build. I'm aiming for it and I hope with time and practice and experience I can be half as good as the writers I admire like the ones who wrote the script for the first season of Arcane: League of Legends (which was RIFE with skills taken directly from stagecraft, intentional or not).
*(Because there's always someone nowadays weaponising disabled people to argue for pushing laziness/exploitation/whatever else in art creation: If you're someone who does care about watching/reading stories but who also does need to have multiple things happening to engage with things, that's valid. My point is that the story should never be written with a focus on explaining things to you. If you can't watch/read a story because it's too difficult to focus on, then complain that the writing was bad because it didn't explain everything to you, that is genuinely your own problem to sort out and I say this as a neurodivergent person who hasn't been able to read most books in over a decade because my attention span for reading is shot to hell. That's not the writer's problem; it's mine. I would much rather they write a good, living narrative (and make it so I need to hold a stim toy in my hand or take breaks from and come back or - in the case of film and TV - pause to process and take breaks from and come back later, or any other type of managing skill) than dumb everything down for me and treat me like I'm an idiot just because I was struggling to focus for longer periods of time.
'Accessible' doesn't mean throw all basic storytelling skills out the window. ADHD/Autistic and other types of neurodiverse people like us have been engaging in media without it being spoon-fed to them just fine for as long as storytelling has existed. It's far more ableist to argue that we should destroy every creative art and new creation in existence to talk down to the audience just in case they're neurodivergent or something than it is to just expect they're smart enough to keep up or at least figure out ways of managing their needs on their end so they can enjoy the story.
Things like proper captions and considering different mediums to bring the story to life in better ways for people with different needs are accessibility. Telling story writers to butcher the writing itself because you think the audience will be too stupid to understand otherwise because they're disabled/have accessibility needs is not and is just plain shitty of a position to have.)
** Remember how I said writing advice rules are actually guidelines and you have to play with them to learn where and when and how they actually apply? Well, there are genuine exceptions to this piece of advice as well. But you're going to have to understand why it's like this first to learn what those exceptions are and how/when/where to apply them.
(One quick example are stories which actively break the fourth wall. Kids plays/educational programs/etc for younger children do this all the time as a way to pull more engagement from the audience because the majority of younger children do need constant stimuli and usually haven't developed the ability to passively engage with something that doesn't directly talk to them/act like they're there in some way.
But there are other exceptions too in adults' media which aren't just lazy writing because they're intentional with a specific reason for doing it outside of "we need to force feed as much information to our audience as possible in as few minutes as possible because we expect every single one of them to only be looking at the screen every few minutes for a few minutes at a time and if we don't tell them everything they'll be confused; fuck, how do we- ooh ok, have the characters talk like they never would specifically so we can spoon-feed the info to the audience. Phew. Done. Ok. Next scene!! Speedrun music, let's go!!!!"
There's a difference between intentional, well thought out fourth wall breaking vs "we don't have time for basic visual storytelling or any other non-direct-expositional storytelling techniques and we're expecting every single one of our audience to have lost media literacy skills and we're not going to risk an easy several billion dollars in box-office and merch sales expecting them to just... get better at it again if they want to engage with and understand our stories properly."
But you'll need to go out and look for and analyse and understand all these different types of storytelling and explore a bit yourself to get a grasp of all the amazing directions you can go with storycraft.)
Basically, go have conversations, watch how people talk, go learn stagecraft in some hopefully-good drama classes, and above all else, KEEP WRITING. KEEP PRACTICING. KEEP MAKING MISTAKES AND LEARNING AND ALLOWING YOURSELF TO BE FLEXIBLE.
And one day, if you're really lucky, you'll hold the tiny little heartbeat of an organic, living story in your hands.
