This is a question someone asked in FMS (the forums in Freenet). The current answer is short, it might expand.
From all forms of government, Democracy has the lowest amount of power-over-others.
Add all power that people have over others. Think it through (power can come from information control, from crypto-contracts, from loyalty of armed people, …).
Add the principle of subsidiarity, which is part of the core of modern democracies (decide on the lowest level that can decide — those affected by something decide about it).
Add the rule of law (laws must be written and general; they apply the same way to people who are practically the same — take actual differences into account but do not create differences where there are none).
For things I’m missing here, look at further General principles of the European Union law.
Then, starting from the idea that you want to minimize power-over-others and thinking it through, democracy is where you end up.
This is also a good metric to compare implementations of democracy to each other: How well do they minimize power-over-others?