I want to be a writer when I become an adult, but I find it really hard to stick to a story and see it through to the end. I feel like I run out of writing juice. The only thing I've finished was this play that I wrote, which I'm currently rereading and editing. I decided to get to work on novel writing again. The problem is, I have a good story line (& plot) all mapped out, but I find it hard to start from chapter one (I kind of started writing chapter three first). Does anyone have any advice about writing? How do you motivate yourself when you're stuck?