Knowing is only half the battle, but if you have no idea what you are actually doing, you'll create a bad Tulpa. I had one since the beginning of April 2004, but now I have doubts that she even is a Tulpa now that she was actually the one who has been telling me not to do half of the things I've been planning on doing that would have harmed myself or others like suicide or stuff like that.
A Forced Tulpa is the worst thing you could do, so if anyone does go for a tulpa, then be sure not to create one with negative feelings. Tulpa themselves, like us, have a moral code. If created and treated with negativity, they'll most likely be bad, if created with love and kindness, they'll likely be best friends. I'm not exactly pushing anyone to getting one since most of the people on the website despise them for how dangerous they can be but they also can be like us.