A writer who reads a lot
Someone who is willing to put in the work to finish a story and is willing to improve it for the better.
There are a lot of people who want to be a writer, but it takes a lot of self discipline to see that vision to the end especially if it's a big project. And often it doesn't end there- there's a lot of editing and improving that can be achieved if a person is willing to look at their own work critically.
Self-critique is very important in my opinion.
Yeah, I think you listed two pretty important ones: criticism and lived experiences. As a note about experiencing life, I don’t think necessarily means traveling the world or trying everything once. Rather, I think as we grow older, develop passions and careers, we learn how the world works and how people behave. I think this is important for developing characters and a world that feels “real”. Understanding how laws, money, and businesses work is important for understanding how to make realistic variations of those societal rules.
I super agree with this answer! 
🏻 Absolutely empathy is important. Unfortunately this usually requires talking to people, which usually requires putting on pants and leaving the house, so that sucks. 
Omg yes!!! I had this revelation a year ago that transformed my writing. I realized I shouldn’t try to create this perfect, “good” book that followed all the rules I’d learned and copied the greats (according to me greats at least). I just decided to write what I thought was fun to me and it frees me from this stress of being “great”. Now I just try to write something that I enjoy reading and it usually works out alright.
A good writer never loses sight of the purpose of what they're writing.
If they write advertising copy, they understand that the aim is to highlight the best features of the product to the specific sort of audience they're aiming for.
If they write literary fiction, they understand that they should create a powerful experience that makes people think and show off their mastery of the written language.
If they write popular fiction, they understand that they should use accessible vocabulary and write a short, tight story that delivers on the expected tropes of the genre they're in and entertains the reader.
Bad writers get too wrapped up in themselves to think about the audience. They'll let their favourite scenes drag on and waste the reader's time to indulge themselves, they'll use inappropriately fancy vocabulary to show off how clever they are and exclude ESL readers on a popular light fiction focused platform with international readers like Tapas and when people don't read their work, instead of looking at whether what they're making and how they present and market it is appropriate to the audience, they blame the audience like, "Oh, they just can't appreciate my art because they're too stupid!" or they blame the platform like "Hmph! Tapas is trying to hide my work because it's too clever and challenging!" It's all about me, me, me.
Hmmmm.... based on my experiences working with writers:
They respect the artist as the other half of the storytelling duo and know when to hold off adding dialogue or narration and just let the art do the talking. They listen when the artist makes suggestions about panelling, character design or other areas where the artist is probably more experienced, instead of treating the artist like an art monkey who just illustrates their amazing words. Oh and they don't think their name should be the only one on the cover.
They use clear, consistent formatting for their scripts. Doesn't need to be industry standard, just easy to follow.
They have studied panel layout and visual storytelling so that even if their drawing isn't the best so they'd probably never be an artist, they don't try to dictate the panelling to the artist while clearly not understanding how panels work. So they don't try to fit things that ought to be 2-3 panels into one like "John enters the room and sighs as he drops his briefcase, noticing the smell from the kitchen," or put a complex establishing shot on a page that has 7+ panels on it.
They don't put too much text per panel or speech bubble. They understand that a sentence or two is enough, and that more writing doesn't equal better writing.
Very good answer again, especially point number 3.
A good comic script writer has to understand comics, know about storyboarding etc.
and has to empathize with the artist who is reading the script
I’ll just try to mention something I haven’t seen mentioned yet: a daily writing schedule. I read a book a while back that just described the work habits of famous writers and artists and it didn’t surprise me to see that most of them (in all categories of creatives) maintained strict working hours. Even some of the outwardly chaotic and artsy seeming still maintained a very orderly work flow. It was actually kinda rare to find one that was like “I write whenever the muse strikes me.” A lot of em were more like “I write every morning no matter what.”
An article: https://jamesclear.com/daily-routines-writers
The book I read: https://www.masoncurrey.com/daily-rituals
This one is big for me. Writers should be willing to teach but also teachable. I've seen SEVERAL writers who aren't necessarily "popular" lord over newbie writers the number of books they've written and their USA Today Best Seller title. They don't mention that that title was earned because they managed to sell a certain number of books.
Bit of a disagreement here with the mastery of the English Language. If you're talking about writers in English speaking countries, yes, but what about France? China? Italy, Brazil, etc. Also, education is not a prerequisite. Samuel Clemens, aka Mark Twain wasn't educated beyond grade school.
to me a good trait for a writer to have is serving the story. They, the writer, comes second, you don't think about yourself or how people will want to meet you or what people will think of you. You want them to want to meet your characters, to know more about them, to think about them, not you. You're just a sidekick who's along for the ride. You're always thinking: will this turn of events serve the story, will it further it, will it flesh it out more. If I change this will it lessen the impact of what happens to the characters or will is strengthen them. It's all about the story.
For me, what really separates a good writer from a bad writer is the element of respect. These writers respect their readers as human beings and their characters as human beings, too. Good writers are usually straight to the point, too.
I think I have a short list of traits I can think of.
Self awareness- the ability to not only understand ourselves in reality but also how our mindsets feelings and experiences control what and how we write.
Dedicated- Anyone can be a writer, but you're not an author until you finish an actual book. It's not always easy but we have to push ourselves to work and eventually complete our work.
Creativity- so many people think that Creativity is the ability to make anything, but I'd argue Creativity is the ability to make something good while working under restrictions and guidelines. Showing that you can craft a world with rules and keep your characters restricted to those rules while telling a good story is something I feel a lot of people struggle with.
Confidence- It's easy to write a story about something controversial like race, sex, politics, so on and so on, but you need Confidence to actually present that story to the world.
Self motivation- there is no guarantee that your book will become popular. Yes, you should probably write for an audience, but commit to finishing your projects for you first. You need the strength to put out book after book regardless of whether or not anyone is reading yet.
Good writers:
1.All writers have to learn set-up/pay-off. Everything should either be setting something up or paying something off. Everything else is literally wasted time. Nothing is worst that having plot lines disappear or have a chapter/episode introduce something and it's never mentioned again.
2. Don't have characters for characters sake. If the character doesn't have a purpose for the story, they shouldn't be there. If you have to look for something for a character to do, they really shouldn't be there.
3. Characters should not be an absolute mess of a personality unless you are writing an over the top comedy. Most sitcom characters could never exist in the real world. They have borderline personality disorders that wouldn't allow them to function in society.
4. Dialogue should be short and "punchy". No one really talks in monologues or explains what they are doing while they do it.
5. Understand a panel can only usually have one form of action. "the bad guy punches the good guy while circling him to get behind him and the good guy falls to the ground". That is going to be a mess of a panel.
6. Respect panel space. Whether you have scrolling panel problems (you can't do splash pages well or big landscapes because of dpi limitations) or traditional panel problems (having 9 panels on a page, then having one of those panels have 4 main characters and a villain in it. They will be tiny stick figures).
7. Understand reveal. If you want a surprise, you need to find out what page its on so the read turns to it. Too many artist give away the reveal by having it on the right hand page (traditional comic left to right) where the readers eye has already wondered a glace over to it. This is a basic structure thing.
8. Finally, every episode/issue has to have something happen. The story must move forward. Even if it's setting something up, it has to be there. Filler episodes are lazy writing. Treat your audience's time with respect. They are giving you their attention, make it worth their time doing that.
Some people claim that (as far as reading & writing go) grade school back in Twain's days was better than what is doled out today. But that's a different story...
-A genuine love for how stories work
-Respect for your readers
-Ability to understand people and question your own assumptions
Description of what I mean by the last thing stolen from my own blogpost below
Summary
First, how well can you get into a characters mind. What does it really mean to choose to go and and fight a monster with a rusty sword? To fall in love with a sworn rival? To be raised in brutal competition for inheritance? Anyone can write these things happening, but it takes a really good writer to actually make them feel real.
Understanding people, how they work, how they feel, how they vary, is what breathes life into a story for me. When I call this empathy, I don’t mean that people who have trouble with social signals or forming emotional connections can’t write well. What I think truly holds an author back is a limited view, and an unwillingness to think about what they’re putting on the page really means.
Second, vulnerability. Connect to a character, then let them be flawed. Admit how frightening it would be to be terrified, and the bravery it would take to go forward anyway. Be willing to question your worldview, and connect with worldviews you don’t agree with.
I think writing well often means letting go of your own narratives. So often, a writer’s own fears and bitterness seep through. If you can’t face those parts of yourself and write them on purpose, you write them on accident.