I mean I can give you some ideas, but I'm not sure that it would help.
Tbh I often ask myself questions, like "how did I get here", "what was I thinking about a moment ago", "what was I before I was born, or before my first memory", "how can I be having this experience right now", "how can I be in this body", and so on. These ideas don't necessarily have to make sense, but they lead me into a certain type of thinking, primarily in the sense that I don't just accept the world around me. However I don't really do this intentionally, it's just something I've become more and more fixated on over the years, it's led me to have some pretty strange experiences. So it's not accurate to say that the thought leads to the feeling, it's more like the other way around, but then the thoughts further enhance the previous intuition. Often I don't feel connected to any of my life experiences, not even to my own family members.
Basically to feel like an experience you create is real, then you must already feel detached from the physical world, and aside from drugs, I don't know for sure that this can be done willingly. Again I don't know for certain, but logically I'm guessing there was something that made me this way, as I can remember what it was like before I felt like this. The only way I can describe it is something like the contrast between sleep and wakefulness, but obviously to a lesser extent. It's hard to put into words which make sense to anyone else, but thinking about myself from a few years ago, it's as if I were a robot, as if I had forgotten something important and I couldn't figure out what it was, as if I had something very eerie right in front of my field of vision, always present, but I went over a decade without noticing it.
But tbh I don't think you have to feel like this to create a tulpa if you wanted to, I believe there are guides but I can't speak for their effectiveness as I didn't even realize that I had created a tulpa until people told me that's what I had done. I guess I've already posted about what I did before, but I think the important bit is consistently thinking about and visualizing her, and at first I only did so when I was going to sleep, that's still when I do it the most. Just make the that the environment is the same, in my case when I was going to sleep I didn't imagine myself in my bed, but somewhere else. However I only tried to have her actually "talk" to me after the idea was given to me. It's essentially like normal thoughts, except the thoughts don't feel like they "belong" to me, and they're not in my own voice. It's a strange experience at first.
