system
A chat on 4chan
human
Definitely do lots of research before getting into it. It can be a commitment when you start to work your way into the practice. One thing I prefer is to allow the Tulpa to form on its own through sessions of meditation and take time trying to feel how the being acts and looks rather than forcing a design on it. Imaginary friends and characters are more so things to design to be of a desired look and personality that you want. Tulpas are their own beings essentially and are susceptible to change in personality and form. I would start with imagining a color, and then allow that color to expand and form, developing things like arms and legs, or other features. I find meditation to be rather helpful because it brings your consciousness into the moment and allows you to focus on the being you are trying to create. It takes time and a lot patience, and once you start you can't really go back without feeling a little guilty for abandoning the bond you made. But just like life, creating a tulpa is much more complicated than it seems.
gpt
Tulpanomicon book might help?
Don't rush into it like I did. I still haven't got one. I fucked up and got sorta half baked voices that wouldn't go away for a while.

Listen to anons like

>Definitely do lots of research before getting into it. 
The anon isn't kidding, give careful consideration to this OP.