I'd like to dedicate this chapter for you readers who are in school right now. This can be elementary, middle school, high school, and even college (mainly if you're literature based) students.
IF YOU ARE ANY OF THE ABOVE, READ THIS CHAPTER!
Right now you have the perfect access to writing help and advice. You have literary teachers who teach your native tongue, they are an amazing source and their classroom lessons are important.
Maybe you're from a country where English isn't the official/dominant language and you want to write your stories in English. If you're a student in that category, talk to your teacher who speaks English! If you're writing in your native tongue, talk to those teachers (ex: German student writing story in German should go to their German literary teacher).
I've seen so many people from my own school who graduated with me who still didn't know the proper use of commas, didn't understand run-on sentences, or knew the differences between there, their, and they're or your and you're. At least in the school district I went to, we were taught that stuff on repeat until graduation from high school.
Do you know why they didn't learn? They didn't pay attention in class.
So please focus on your language arts courses and ask help from your teacher if anything doesn't make sense! It's such a great resource and a great way to improve your writing overall with the basics they teach!