People who think true world peace is unachievable and joking this ain't Naruto, well for them it's really is unachievable or that they'll die a death of fodder. Now as for the question, true peace is a dream worth chasing. There is only one way to go with it. Uniting the use of power and understanding. First thing that is necessary is power. You can't do shit without it. So first of all one must gather and summon and work for obtaining the utmost power. Then from there, two ways leads to peace.
1. Try to make other powerful people and the mobs to understand your views, by meeting them and talking things out. This is the lengthy method. It involves lot of hardship and maybe in the end failure as well unless your successor has the same mindset as you.
2. Give the world a common enemy. This is a short method in my view. DO as much destruction as you can to not just one but every country so that all can see you as a threat worth fighting together. Then just simply start the ****ing war with full force, no mercy. Then simply fight it to the end and leave the rest to nature. Survivor of the fittest. If you win, lead the world as one. If you lose, then simply die, in which case you can be sure that at-least you united them for once. Then from there on, it'll depend on the survivors to make things out. After such a war, I hardly think people would like to experience this again.
Eitherway, it will be a life worth dying for.