I haven't studied any of them that much yet but I have a good jist.

RSD - self improvement, self realisation: summed up brilliantly by "being, not doing". So rather than doing something to get a girl, you just are that person who girls want.

MM - Mystery's first method of teaching. Very methodical as you'd guess. Far less examination of yourself and more on what the girls think and do.

Annihlation - Style's way. From what I've watched, a bit similar to MM, just with Style's thought process (so bits and pieces of self improvement).