For therapy to be effective then, it has to be fluid and tailored to the individual person. Having said that however, there is something that I keep coming back to time and time again.
Everything we do in life is a behaviour, and all of our behaviours are motivated by one of two things. To feel good, or to avoid pain. Whether we realise it or not, in order to feel good we strive to satisfy the basic psychological needs that all of us have. It's not possible to be happy unless we are satisfactorily meeting these needs.