>>25000987there's no quick way about it, time is the biggest investment that a tulpa takes.
as for how to start, it's best to begin by understanding what a tulpa is, because if you believe in the occult side of things (and many do i'm afraid), you're just asking for trouble
you must be able to accept (and over time, truly believe) in a subjective reality. that is, your tulpa does not exist, but it does exist for you. if you can't see yourself doing this, don't bother. a bit of doubt is healthy, though, and will disappear with time
if that seems all well and good, then the formation of a tulpa starts with accepting that it exists, right out of the gate. maybe you don't have an idea for it's form/personality yet; don't worry about it, that's all secondary to accepting it as an entity.
the best way for a tulpa to 'grow' is through conversation. just talk to it, all the time, no matter what you're doing keep it in your thoughts. easier said than done, but that's the most important thing, i think. it won't be talking back right away, but that's fine and can take awhile (a few months to over a year for some)
meditation is a good practice to pick up for this, so you can focus on nothing else
back in the day it was said to require 100 hours or so of undivided attention, but idk really. it's too subjective a thing to really quantify in that way