Usually, it's people you've worked with before and that want to work with you again. You call X, you say: quit your job, work with me on this. Failing this (wh

Usually, it's people you've worked with before and that want to work with you again. You call X, you say: quit your job, work with me on this. Failing this (which might be the case), find that first person, give them equity, and they will find those people.