You have, hopefully, analyzed your writing and have identified those areas where your skill level needs the most improvement. What specific steps are you taking to improve those skill areas? What drills, exercises, etc. are you using to improve those skill areas? Which authors are you studying to learn from?
I come to this forum. I read books. I research theories and methods for writing. I'm probably not far enough advanced to really worry specifically. I just measure my self against which ever author I'm reading at the time. Currently Margaret Atwood
I want to know what really good writers have to say about this, and what they did. Tad Williams told me when I was a teenager that you just have to write every day, even if you're depressed or tired or feeling like you're in writer's block. He said you just have to write, and over time you get better with practice. I saw a cool meme on Tumblr a few months ago telling the story of this woman who would be at parties and other social events telling people who she is planning on writing a novel, and how she would every now and then impulse buy a book on how to write better, whereas this other woman signed up for writer's workshops, wrote and wrote, got stuff rejected by publishers, did a graduate program, kept at it, didn't really even talk about it, and eventually got her own TV show on the air. I think it really probably is like everything else. You get motivated and determined and go crazy with a thing and just do it. I worry sometimes that I'm just not intelligent enough sometimes. I read stuff and wonder if my attention and memory is good enough to actually retain enough info to be a good enough reader to be a good enough writer, but I still think writing is fun and satisfying.
First, I write. You have to have something down on paper that you can improve upon. Second, I not only read best-selling authors, but I study their styles and the techniques they use to deliver a great story. Third, I seek lots of feedback (and offer it in exchange). And forth, revise, revise, revise. It takes time and effort to craft a good story.
This is really important. When I read a book that really rings my chimes, I go back and read it again to determine why. It's the only way to determine if your writing is doing what you want it to do. I spent almost as much time reviewing and revising my recently-completed project as I did writing it in the first place.
I've read literally thousands of books and continue to read. I've also written a lot. By now I have a pretty good idea of my own style. However it often changes depending on the genre and period. If I'm writing a Victorian novel, I try to adopt just a hint of the style of the writers of that period, and so on. Sometimes the main characters affect the style of the narration as well. I seldom revise a lot except to correct errors. Generally I have a very good vision of the flow of events as I write and moving stuff around often simply isn't practical.
Reading mostly, recognising why some author's style of writing works for me and others don't. Interacting with this forum - a wealth of information. Watching TV - movies mostly - probably not the most conventional way to improve writing skills but its the plots I'm interested in - I hate an obvious ending and 9 out of 10 times guess whats going to happen - if they fool me I love it - that's what I want to accomplish in my book. Trawling the internet for writing tips.
I am going back and analyzing books I've read in the past. I'm also paying closer attention to everything new I read. The best practice is learning from already established authors. I'm also reading a few books specifically about writing: The Complete Handbook of Novel Writing (Recommended by @jannert), The Complete Guide to Writing Great Fiction, Writer's Clinic, Plot & Structure. They are all books published by Writer's Digest.
The search-and-destroy/replace function on a wordprocessor is a great editing tool. If I suspect I'm doing something too often—overusing a particular word, etc—I search it out and see how often it actually comes up in my MS. After going through a 36-chapter novel with this device rolling, you can bet your boots I'll think twice before EVER using that word or phrase again!
Beacause I don't get a lot of reading time, I do what I can to study craft. I'm addicted to the "Writing Excuses" podcast because it's usable as curriculum and I can listen to it while doing other things. And I hang out on the forum too much. Going to my weekly writing group also helps because I get to see other people's tricks, examples of good writing, and enough examples of bad or "not quite there" writing to learn to pick up on other people's mistakes (which I think informs my view of my own text).
I write things that are never intended for publication. They may be stand-alone stories or they may relate to my WIP, but when I write them, I know that they are only kindling for the fire. I have no citable evidence, but forum conversation often leads me to believe that many people would find this to be very odd behavior indeed. The idea that you might write a scene in your story that will never be in your story, on purpose, seems counterproductive to some, but not to me. I am here to improve as a writer; I'm not here to just improve a piece of writing. Most of my own items that I post in the Workshop answer to this description.
This is an interesting topic. I know it's common for successful authors to say that you need to read a lot to become a writer. And that makes sense because reading helps you to learn the technical side of writing. How to do time and scene transitions. How to write dialogue. How to develop characters and keep a smooth flow, and so on. But it also occurred to me that writing is its own language. That it's supposed to portray life, or a reality of some sort, but it does so in a certain and artistic way. Have you ever visited friends or family in another part of your given country, and found yourself adopting their dialect after a few days? I believe this same principle applies to reading a lot. It adapts your mind to thinking, speaking, and most importantly, writing in a specific way. My personal approach is probably a combination of what everyone does to some extent. I do the common things such as read a lot, but pay attention to the authors style and writing as I enjoy the story. I read about word mechanics, and how to use punctuation and improve grammar. What I've recently been doing, and found it helps a lot, is questioning paragraphs and sentences of my stories in relation to what comes before and after them, and does it flow smoothly and make sense.
I've said many times on this forum that I work this way, too! I write scenes involving my characters just to help me get to know them better, if they seem a bit foggy to me. These scenes won't be in the final story, and I know that, but they certainly help.
I can never study other authors' works, because when I try I get too sucked into the story, and before you know it I've reached 'the end,' and haven't taken note of any techniques at all. Seriously. HOWEVER, storytelling style does seep in subliminally. I am learning. If you read voraciously, it will 'rub off' on you, even without direct study. You'll look at a sentence you wrote and you know it's not right. Your spelling and punctuation skills become second-nature. You know how a story rolls along, and while you may make beginner's mistakes, you'll find them easy to recognise and correct once you start doing edits. You know what a story should look like and sound like, if you're a great reader. It becomes easier to write and attribute dialogue, and to structure your story so that it doesn't get stuck. It isn't absolutely necessary to be a voracious reader, if you're a writer as well, but it damn sure helps.
I keep a list of things to search for including anything which ends with 'ing' or 'ly', also the words 'has,' 'is,' 'had,' etc. I delete about 98% of the words I find. I use Libreoffice which doesn't let me search on regular expressions. so this can be a slow process.