I am a new DM, and I am quite good at running encounters, making interesting environments to explore and creating compelling NPCs. I struggle with the storytelling aspects of the game. I know the sort of story I want to tell but I'm not sure how to tell it.
I feel that I need to use pre-written adventures as a crutch to avoid burnout, but I don't know how to take an existing story and add in all the elements I want to have.