One thing that is very common in A LOT of fanfictions is GRAMMAR MISTAKES!
It's really difficult to understand a lot of FanFics when they have grammar mistakes. Here's why:
          When you write, you want to make sure that your reader understands what you're saying and/or explaining. If you're not a native/fluent English speaker, when you write, it doesn't make much sense. I am not trying to be offensive at all in any way, but it never hurts to have an editor. I am currently an editor for one of my friends here on AFF since she doesn't have the best grammar. I'd be happy to be your editor, I have a lot of free time. :)
          I do not recommend using Google Translate. Yes it does help you translate SOME sentences and words, but it doesn't always give you the right way. Believe me, Google doesn't have the answers to everything. (no offense to Google)

          If you ARE a native/fluent English speaker then you should EDIT your chapters more. You really should, not just for the readers' benefit, but for yours as well. When you edit your chapters, you can rethink things better and change this sentence to a better one.

Some examples of grammar mistakes are just like where the commas should be and apostrophes > '. A lot of the time I see these " with spaces like this:

" And then I fell in love with Jungkook. "

          No, please no. Those don't ever have spaces. If you do this, you don't understand how many grammar rules y