what to write

I dont know what to write about I am so conffuesed this always makes myy grade  go down because I cant figure out what to write.  i have asked many people they do not help I tried a website called story starters I just cant seem to find a topic that sticks.  please I need some help one of my freinds brenden kept on saying write about this write about that it was terrebly conffusing.  So i am just sitting here thinking.