First it would be simple. I would start by political dissension of large countries. USA, Germany, Russia, UK, France, Japan. Those countries would be put into utter disarray when civil wars started. After those were quelled I would put my advisers in charge of each nation, getting them in on platforms that appeal to everyone. I would dissolve their senates and what not, making my advisers complete leaders of the countries with very little opposition. They would step down and leave me in charge of each one, changing the rules of each country so I was able to. With these nations under my command, I would start a war that would lead to the rest of the free world coming under my rule. The nations would be united under one flag, under one person, and under one rule. Rule being my own, not like...There are no rules rule. That's stupid. After that, it would be Iron Fist. If you don't accept the nations, you are simply killed. No second chances, no nothing. I'm not gonna let you rise up with your resistances. Then I would start uniting the industries under one command. Steel Makers, Quarries, Agricultural, which would in turn lower the cost and production if all companies work together.
After global prosperity becomes a dream come true, I would then take to technological research, having specific groups of scientists working under certain projects. Teleportation, Space Travel, Renewable Resource, Terraforming, World Regression (Which would be in essence restoring the natural resources of our world).
I'd let people worship who they wanted, under the sole conditions that no one is killed for their religion, no one suicides, nothing. Also Scientology would probably be under heavy scrutiny. No cults would survive very long. Unless it's a suicide cult then I'll give them their own high security island to be monitored on. Just in case they don't follow through.
If that all fails, nuclear winter.