Chris, the pharaoh, backed by the priests, did have some tricks up his sleeve. Some Egyptian temples had sophisticated ways of measuring the water levels in the Nile and could “predict” the annual floods before anyone else noticed the changes in the levels. Priests typically were the only people who were literate.
Of course, none of this means that the pharaoh and priests did not actually believe what they were doing was real.
Succession within dynasties was through family inheritance (often matrilineal, which is why pharaohs often married their sisters). A transition between dynasties sometimes involved violent conflict where one family overthrew another. This was not the norm; Egypt had stable political succession for the most part.