Okay I know I know, more rules but this is important.
I know fan fictions are a lot of fun but there have to be some boundaries.
First off, don't go to far. meaning stick to kissing, no graphic makeout scenes, or sexual content. Keep them PG-13, don't even think about going to R or even worse NC-17.
Secondly, no cussing. I know in real life you cuss everyday but keep it PG-13 again, no F-words, S-words or anything like that.
Thirdly, no personally pinpointing one person. Asking for parts is okay but say you have a mean person in your story, and you think of Sally, who's also on the forum, she's not your favorite person, so you decide you'll use her to sabatoge you and Derek's relationship. Yea, that's not nice, and I'm sure she'd report you to me, in which case I'd have to send you those incredibly annoying warning messages.
Enjoy, write have a good time, just follow the easy, fun, happy-go-lucky rules!