When you start a book that is quite different from what you've been writing....

It's hard to break out of old patterns. It might help to start with some exercises, and also reading new things like what you're aiming to write to sort of immerse yourself in what you're up to now. Write a little fanfiction in a similar type of story (it's easier to isolate the area you need practice with by picking the right fanfic to write). You can force yourself to just keep writing the new stuff, even if it's bad, because sometimes that's how you get better at.

For a more meditative type of approach, take a moment to breathe and all, but then try to picture the person you're writing your story to, like a letter. Maybe it's a real person, maybe it's not. But imagine you're writing to this person, instead of for yourself. How do you talk to that person? How do you get that person to smile? Do you talk slower or faster? More detail or less? Tell them about your character. Your story. Tell them out loud what you're trying to do with the scene, or the character, or whatever other spot you're working on. Talk through it, but focus on talking about it to this other person, to get out of your own head.

For another angle, maybe your new writing doesn't need to be that much different from your old writing after all. Maybe you just need to find your groove, and figure out how your style meshes right with this story, and it's just a bit of anxiety holding you up. Maybe it's all head games, and you just need to relax, let them go, and get to work.

 

Oh. Well, personally I just try to play around with the ideas and have fun with it, and usually stumble into some new writing tricks along with the way.