Stop having teenagers propose to each other.
Don't use pink as the international symbol for girls and girly things and love and hugs and kisses or whatever.
Make taunts taunting. It is not offensive if you say, "You're so stupid."
NEITHER MARRIAGE NOR PREGNANCY ARE GOOD PLOT TWISTS!
Stop being the humble saint. It is not solely your boyfriend who might cheat. If your character has flaws, s/he might also cheat, so don't try to come off as the perfect person because I will punch you.
YOU ARE READING
Tips For Writing Fanfiction
RandomExactly what the title says. (If you have questions, you can PM me. I'll try to help. Or, you know, take any insults you want to throw at me.)