- FIRST OF ALL: READ. Reading is the best way to improve your writing. And read books/fics of the quality (or superior) of the quality you want to write. Your writing reflects your reading, so if you read simple books with a little description, it won't enrich your writing.

- If you're going to write, do it on a proper document. Word, Notes, or whatever. I heard more than one writer complaining about Watt erasing a chapter out of nowhere (maybe they fixed this bug, but I still don't trust it).

- Put this doc in a cloud. Dropbox, Outlook or whatever. This way, even if for some reason your phone, pc, or tablet fries, your progress is saved.

- Font is important. Choose a font that doesn't look over professional, like TNR. I use Calibri, some prefer Comic Sans; test some and pick the one that better fits your personality. The important thing is to be light, to not make your eyes hurt and not make you feel pressured. And yes, zoom that in and keep a safe distance from the screen without having trouble to read (I'm currently at 75cm from my screen – more or like two feet and something)

- POV: you either do it in first person or third. Choose one and STICK to it. I read a hundred of fics and dropped another two hundred because the author kept switching from first to third to back to first. This is TERRIBLE, so choose one. "Oh, but I want to do it in first person to show the characters thoughts". Great, then do it. But if you have trouble sticking to first person, remember there is omniscient narrator, where you can describe their thoughts "X started to panic, remembering that time when Y said W to them, and wondering if that wasn't a terrible idea after all, cursing themselves for being so stupid". There, problem solved.

- Formatting is important. 'Enter' is a hell of a tool. I remember seeing a post on tumblr that you should always start a new paragraph when you change: TIme, Place, TOpic, Person (TIPTOP). Even if you have a giant monologue, split it. Put an action in the middle of it. "Monologue monologue monologue" X stood up and moved closer to the window, their eyes lost watching the rain that hit the glass, adjusting the blanket over their shoulders closer to their skin. "Monologue monologue monologue". There, you split a enormous chapter and even showed the mood. Oh, Word is also nice because it also puts the capital letters when they are needed, like the start of a sentence (watt doesn't),

- Length is something only you can know. Depends on how fast you can write, if you do it on your pc or phone (I have a hundred 5k words chapters because I always write on my pc, if I had to use my phone I wouldn't have made it pass chapter 15), how fast is your story's pace, etc. In my experience, a good start is around 800 words. It's not that hard to write 800 words per chapter, but is still long enough to scratch your readers' itch, at least a little bit.

- GRAMMAR. I know, grammar. To those who don't know, I started writing my fic mostly to train. I'm not an English native speaker and I was mostly self-taught with reading. I reread my first chapters and my English at the time was embarrassing. But it also makes me realize how much I improved over the last 4 years. My grammar was a problem, of course, so now I have four tiny technics I use and I will list them here: 

1 – DICTIONARY, I have an offline one in my phone, so sometimes I'm like "is there an S before the C in this word?" and then go check (I write a couple of letters and it starts suggesting words). If you're not a native speaker, having a translator also helps. Oh yes, and it lets you know if the word ACTUALLY means it "You keep using that word, but I don't think it means what you think it means"; 

2 – SYNONYMOUS (yes, I had to check the spelling, because I wasn't sure if it was YY or IY). There are some things all over the internet to help you find the word you're looking for. I have three, one is for feelings (by Kaitlin Robbs), where it goes from the basis (anger, fear, surprise, happy, disgust, sad) and allows you to narrow it down. Another is 128 words to use instead of "very". So it gives you "very accurate – exact" or "very loud – thunderous". The last one is a bit different. It has the basis, that offers you the verb and than the subject. So from APPLICATION, it gives me apply, modify, build, solve, etc to use with diagram, forecast, list, project. From KNOWLEDGE, it gives me write, list, recite, draw, identify, etc, to use with people, definitions, recordings, magazine articles; 

3 – GRAMMARLY, to those who never heard about it, it's a program with a free version that you can download to use with Word or the internet and it finds the most obvious mistakes (a misspelling, oxford comma, wrong conjugation, etc); 

4 – REVIEW, so simple and so complex. You just have to trick your brain. Write your chapter. Wait a day or two. Change the settings as much as you can (I take from Word, put it on Watt and read the preview in dark mode). Basically, when you are rereading right after you wrote and in the same setting (mind you, you should ALSO do it), your brain starts to ignore some mistakes that should be obvious, so when you change the settings and give yourself some distance, your brain is more likely to find those mistakes.