There is no one way to answer this question, because totalitarian regimes come to power in various ways. In light of this let me list a few important qualities that totalitarian regimes share.
First, all totalitarian regimes need military power. Brute force is necessary to control the masses. So, these regimes need the force and support of the military.
Second, they need to create ideology that justifies their power. The most effective way to do this is to make it seem that their power is good for the people. Some post-modern theory can be important here. Foucault says:
"Each society has its régime of truth, its ‘general politics’ of truth: that is, the types of discourses which it accepts and makes function as truth; the mechanisms and instances which enable one to distinguish true and false statements, the means by which each is sanctioned; the techniques and procedures accorded value in the acquisition of truth; the status of those who are charged with saying what counts as true."
This control of knowledge is also the primary way totalitarian regimes stay in power.
an influencial leader that the crowd, mass population can relate to rises to power through town meetings becoming higher in rank in "unofficial government" formed by the people and then as that individual rises far above, he/she becomes so popular and the public believes so much in him/her that the the government is overthrowned and that person rules instead.