1) Scare the people with false flag attacks, exaggerated threats of foreign and domestic enemies, etc.

2) Present yourself, the would-be dictator, as a strong leader who will protect the people. Specifically, have your political and media lackies set you up as the "Great Leader". You must then "reluctantly" agree to save the country, since you have been "called" by God and the people to do so

3) Have the lackies trumpet you, the Great Leader, and reinforce a constant state of fear and confusion in the people, non-stop -- so that the people gradually transfer all of their allegience to the Great Leader as the only one who can lead the protection efforts to save their backsides

4) Have your lackies viciously attack anyone who questions the Great Leader as undermining the effort to save their backsides, and as helping the "enemy" (if you haven't developed a scary enough myth about the "enemy", go back to step 1)

5) Then the people will become so brainwashed that they'll do the attacking for you of anyone who questions you, the Great Leader

6) Cover and let sit for 5 minutes, and serve with caviar and cabernet.

Oops, wrong recipe... here's number 6:

Rape and plunder your nation's wealth and that of the countries you decide to invade. Spread the wealth around liberally to reward your lackies who helped you get there -- who will include some large defense contractors, media companies, and other corporations, and throw some loot at others you need to bribe to maintain your power.

This method works in any country, in any culture, in any period of time.