I need help for a idea I've got a bit of a start but need help on continuing it it's about two teenagers who fall in love in love with each other. I just want it not to be like a normal love story but it to be tragic. I want it to be different.
Keep in mind cliche isn't necessarily a bad thing. Anything can be whittled down to a cliche if you dissect it enough. Even the best seller books and movies.
The difference is doing it in a way that makes it unique, and like user19388 said, there is no magic potion to help you do that.
Just write, continue to write, tweak your story a little bit, until you have something you feel you, and your readers will be satisfied with.
I think in that case you should just let the story unfold on its own. Since you've already got a start, each step you take you should ask yourself what the possibilities are, what may possibly happen next, and don't settle with just one choice. Brainstorm and list out all the possible options for the next action/scene/twist/... in the story. Then you can choose which one to go for.
Romeo and Juliet, Hamlet, The Fault in Our Stars, I can go on. There's a lot you can do to make it original. But you need to spend the time to brainstorm. You need to spend the time to write. To fail. To write again. If you're committed, you'll find your way (and your ideas). You may start with a cliche template, and then figure out ways to make it more original. But there is no magic potion to help. It's all up to you.
Good luck, and persevere.