Ahem: This may contain similarities to Mr. House in Fallout NV.
Firstly, become the "Supreme CEO" of a Hi-Tech company, somewhere in a communistic country that will let me do as I please so long as they get money and tech. I will train all the best minds I can get, allotting a few of them to the project of my immortality. I will work out of them the best technology I can, and create my own defence / offence weapons grid that will allow me to defend against or attack anything from a respectable distance.
I will also have robotic armies developed, capable of annihilating infantry and vehicles. Also robots useful for sting operations, these will be very necessary.
I will have my tech company buy out other companies in defence and technology once we have enough power and money. As soon as my weapons grid and a sizeable force of robots is operational, I will try to acquire land, money, resources even if I must step on toes, at this point things begin to accelerate.
World leaders, defence bureaus, security and insurance companies will all get into serious trouble caused by hacking and sabotage. This will distract them long enough for me to get my robotics going at full speed.
Then I will escalate terrorism and the hacking, assassinations left right and centre. As soon as I am suspected, I will strike, I will make sure that my company's robotic products were all around the world, And that I could listen to everyone everywhere.
Pull them apart from the inside, then deliver the crushing blow, the invasion force and the powerful ordinance only to finish the job.
Once the world is in a state of wreck and havoc, I give the ultimatum: Join me or get crushed.
I would be world leader, and put some resources into defence, but the rest into infrastructure and rebuilding the world as a better, stronger place. Personal freedoms would be allowed, so long as there was no thought of treason. Normal, happier lives would be encouraged, so long as my orders (which would only be frequent in the early stages) were followed.