hmmm, you already did a school+enemies plot and sm trainee+family plot. so maybe you can try going to the request tabs and co-author with someone heheheXD its been long since i wrote essays for my school so i couldnt think of anything aisshhh. maybe you can try writing
1. fantasies like angels, demons and vampires.
2. maybe forbidden love (reminds me of ukiss)
3. horror+romance such as person A who probably may have a mental problem (he/she became like that maybe after his/her parents met with a tragic incident and people thought the entire family died but he/she actually survived and to make it worse, she was or robbed or smth while on the way home)in that creepy neighborhood but majority of the people living there thinks that he/she is actually dead and haunting that alley/apartment/anything. Then he/she fell for Person B and maybe at first he/she freaked out but he/she had dreams or cannot resist checking out the haunting area and Person B finally realizes that Person A is a human who needs attention and love from another human. And probably that's how love blossom? And then maybe they found out that Person B's father actually was the one who wanted to kill person A's family hence the accident.

Sorry if it is lame, i'm not so good at plots heheheXD but i hope that i may help you get some inspiration for your next story! Hwaiting! :)

just follow your heart! LOL! :))
wth was that advice XD