Your primary point of address is to gain control of the energy of the civilization.
The means by which human being exchange with one another, the money system itself, comprises the energy of a culture. You must therefore set up banking cartels that take from government the role of creating and issuing money. Once you are able to create and issue the money supply, issue it as interest-bearing debt.
Having achieved that, you will find yourself the master of all economic activity, senior to government and able to control events on the planet simply by through the puppet strings of debt, flowing money to those things that suit your purposes and denying money to those human activities inimical to your goal of enslavement.
To make sure nobody twigs what you are doing, hide your basically simple scam behind a smoke screen of complexity and call this baffling complexity "economics." Now you're all set.
Use your control of money to nurture and promote operations that further consolidate your power. Important among these are:
Facilitate the political careers of your proxies in government and hinder the careers of anyone who genuinely seeks to further the cause of human freedom. You do NOT want well-intentioned, capable politicians who seek to serve the interests of their people in any position where they can influence anything. This may give politics a bad name but so what? If politics has a bad name it will be shunned by men of good will and you do not want men of good will to embrace it or meddle in it in any case.
Facilitate the promotion, instigation and carrying out of warfare. Keep human beings fighting one another, keep them afraid of one another, keep them desperate and confused. While thus kept busy slaughtering one another, they will be unable to see and target their true enemy: YOU. This has the added advantage that you can extend limitless loans to desperate governments embroiled in war and thus make a packet on the interest.
Keep human beings and their various groups and endeavours in debt and make sure they never get out of debt. Make sure that debt levels keep on increasing. The more universal the debt, the greater your influence.
Extend your influence through the media. Use the media to ensure that human beings never get information that makes sufficient sense that they can resolve problems. Make human beings believe thereby that problems can not be solved. At the same time, disseminate "information" that will lead them to conclusions that suit your purpose, however daft and however inimical to their own long term survival. Their long term survival is unimportant. Keep them misinformed, afraid and bewildered.
Use your money power, your control of government and your control of the lines of information to nurture the growth of unworkable psychotherapies that actually reduce the ability of human beings to function and which render human beings apathetic and malleable. At every opportunity make sure human beings do not amount to anything or become more able. Dress all this up in the guise of "help" and "healing." Ideal for your purpose is psychiatry, so ensure it is nicely dressed up as "science." Use your political proxies to pass laws that extend its power.
Use this influence to further the cause of drugging as the best and most efficient way to render a population dull and incapable. The importance of drugging everybody you can on any pretext you can dream up can not be overstated.
Make sure that at the same time any workable methods that do arise which make human beings better, more alert, more well and so forth are crushed. Such movements, if allowed to take hold, will jeopardize your whole operation. Be afraid of them.
Use your political proxies and psychiatry to infiltrate and subvert the education system. Make sure thereby that human beings are rendered incapable of reason and the ability to think for themselves. Limited literacy is your goal. You do not want free minds and free minds should be neutralized at every opportunity. Such people make very poor slaves.
Create a climate of confusion. A bewildered or upset human being is grist to your mill.
Given the constraints of distorted economics, misinformation, poor education, drugging, the predominance of debilitating "psychotherapies," and control of the machinery of government, you will have your slave planet, to do with as you will.
The only problem you will encounter then is the fact that no civilization can run when the minds of its individuals are dulled and crippled.
The whole exercise therefore will enable you only to inherit ruins, smoking rubble and corpses.
This may, however, be perfectly acceptable to you if your goal is to destroy the human race.