My very quick ways to improve writing and using tools to help you realize your crutches as a writer and advice for roleplayers and GM's.

https://wordcounttools.com/ This is one of many sites that can help you do these things.

1. Spellcheck, before you post on the thread. It's simple, several browsers (and add on's.) straight up do the work for you and it shows the basic amount of respect that you're putting effort with those you're roleplaying with. Don't do a job, half-assed. Especially a hobby that's supposed to be based on passion and imagination.

2. Check for the words/phrases you're using. (or overusing) The more vocabulary you can use the better. Check with tools. For unique word percentage and it can give you an idea of grade level. (Though not perfectly, because fantasy words will skew it. More complexity doesn't automatically make writing good, though it doesn't really hurt if you know how.) Since roleplaying is an interactive medium between others, you have to make your writing actually interesting. Skip how detailed the bridge their crossing is, no one cares. Eliminate words that you don't need. Add real drama/turmoil. Do whatever to you can to not repeat yourself, quality over quantity is the most important.

3. If you cannot go with the flow when roleplaying, don't do it. GM's just let people have fun and don't add hundreds of unnecessary rules that just confuse most people and aren't followed anyway. You really don't need rule that says, don't god mod. This is obvious. If the rule can be described as "I'm the GM, I have final say." Then just post that. Players don't question or argue with the GM ad-nauseum. If you're the one stupid enough to try to god mod, prepare to be punished for it.

4. If you're going to drop something or go somewhere for a long time, post why and if/when your coming back. There is no excuse. We all live in the real world, everyone values not having their time wasted. It's common courtesy.

5. Have fun, be active and take constructive criticism in your writing. You can only improve when someone tells you about flaws you didn't know you had.