I’d go about it the same way as making a tulpa based on any other character. It’s pretty common to make a tulpa based on a character from a show, book, movie, etc. This is basically the same, but should be somewhat easier since this character is a product of your mind already.
Start out how you might with any tulpa: personality. If you’re a decent writer, you probably already have a pretty good idea of this character’s personality. In a wonderland, void, or mental copy of the room you’re in, sit down with your character and describe their personality in detail to them, like you’re analyzing a really close friend. This accomplishes two things: feeling out anything you don’t already know about this character, and fostering the idea of them as a separate person from you rather than just a concept.
Move on to detailed visualization of his or her form in each sense. Sensory details add to how real they seem to you, which in turn helps bring them to life. It’s also needed if you want to go for imposition.
Of course, narrate as well. Talk to them, in your head or aloud, like they’re another person.
Writing your story can be a form of forcing as well. There are a couple ways you can handle it:
- You’re running this story about your tulpa in your head, narrating it and directing it like a movie. Think of it as similar to telling a child custom-made stories with a self-insert character for them.
- You place your tulpa on a set and puppet actions they do. Puppeting isn’t always bad like some of the guides say it is. You can puppet some with the intention that you’ll move to suggesting actions as they become more aware, and eventually to just watching and controlling the other puppets as they do their thing.
I wouldn’t suggest making the story world their reality. There’s too much possibility of an identity crisis if they discover it was all a fantasy story world and everything they’ve fought so hard to accomplish is meaningless. Immersive story worlds can be fun for a tulpa, are a good addition to forcing, and help keep a young tulpa from being bored. But be sure your tulpa knows it’s a world you’re making for them and that they’re welcome to come see the real world too.