In this question, I proposed a system of democracy for a city state that is being encouraged away from autocratic rule, however the system I proposed appeared to have many faults.
As a bit of background, this is a city state with an area of influence a few hundred kilometres across. Previously, rule was held by a series of vampiric immortal autocrats, and the slayer of an autocrat (which event could only happen during a vampiric ritual) traditionally became the next autocrat. The autocrats were fairly unpopular to the populace due to their vampiric habits, but could not be removed due to their effective immortality and magical invulnerability, and the fact that the latest autocrat had some quite progressive and beneficial ideas that benefited much of the community (that wasn't being drained) significantly. This city state is at a technological level roughly equivalent to early renaissance Europe, though with some magic that isn't particularly significant to this question.
However, an individual has overcome the last autocrat during the ritual, but is so repulsed by it that they want to eliminate the tradition entirely. As such, they want to abdicate their position of power and establish a democracy so that there will be no single autocrat who could re-establish the traditional practise of the vampiric ritual, for long enough that the tradition can no longer said to be the tradition.
This individual has some knowledge of our various democracies, however the citizens of the city state do not have experience of any form of government other than autocratic rule, and any thoughts of democracy would be rare and strictly speculative.
The question:
What form of democracy could be implemented that is easiest for the literate but democracy-ignorant townspeople to understand and practise, which would guarantee that no one person could be considered to be an autocrat for the foreseeable future, and would provide the fewest opportunities for corruption or abuse? Magic can be involved, but the less the better, and preferably won't be required at all.
EDIT:
The townspeople don't actually need to be completely ignorant of democracy. Yes, they had an autocrat, but he was more concerned with finding and consuming his latest victim and enjoying his other lordly prerogatives than with actually doing the work of ruling. It is highly likely that since educated, independent-minded people make better victims, he would have encouraged said education and independence, to a degree.
The townspeople would likely have not wanted to bother their lord with trivialities that could bring them to his attention and result in someone being devoured or executed, so with the lord's tendency to just say "I want this done", and the populace's desire to get the 'this' done without bothering their lord with questions or failures, that they could have developed at least the precursor mindset to democracy by themselves over the course of a few hundred years, by electing their own councils and committees who would oversee the actual work of running the city. The elected officials may not have been the best the city had to offer, but they would have had to be competent in order to avoid lordly displeasure and attention... Democracy then becomes a matter of replacing a largely figurehead autocrat.