Firstly, I'd establish myself as a ludicrously potent military power who, in all honestly, just wants to be left alone. Invitations to join the global community would be politely but firmly rebuffed. I would show aggression to absolutely no-one, at least until I have sufficient arsenals to wipe out everyone should I so desire.
Step two involves taking some time to build a persona. I would become the world's most grand and hilarious super villain. Do I want to take over the world? Maybe, but I'll give it up after 12 hours and let everyone go back to normal while scratching their heads. I won't blow up schools so much as steel major landmarks to decorate my island-nation beach (which, incidentally, anyone is free to return to the original spot). Everything I do is a spectacle and I can get away with anything because, while people will TRY to stop me, they're not going to push too hard once they realize that I'll let them have most of it back without a fuss and if they push me on the few things I DO want, that's what the military I've got is for. Eventually, the world's most popular news topic will be "What on Earth is he going to do next!", which I will happily observe using my satellite tv (the satellite being my own, equiped with death rays of course) while lounging beside a pool filled with jello. I will periodically perform some grand scheme so that no-one ever really gets well and truly board ever again. When people start asking for my demands, I will pick them from a hat, in front of them. I'll never wear the same outfit twice, alternatively selling them on eBay or giving them to orphanages the day I'm done with them. My hair will be dyed bright turquoise and I'll have a strange habit of speaking in limerick every once in a while.
Further, my island nation will ROCK. While I'll be utterly insane to the rest of the world, I'll be the perfect benevolent dictator at home. I'll make damn sure I get enough spoils from everywhere else to make sure everyone is comfortably fed, well educated, and in a decent home. My Evil Army benefits package will be so good that people will defect from OTHER armies to join me and we'll have excellently tailored uniforms (no masks). I'll pay very close attention to the list of overlord tips and make sure to follow as many as I can that make sense (and post relevant ones for my minions). I'll be careful about my trusted lieutenants, but make the entire system run complexly enough that everyone knows that deposing me, the one guy who gets it all, would mean that my usurper would have the rest of his days caught up in annoyance trying to run everything, not to mention the rest of the world would be willing to put up with him/her less.
Here's the catch though: you join my island nation, you stay in the island nation. The only way off is in the military, who are all installed with chips that let me track and speak to them through direct stimulation of the inner ear. Then I look like a MAGICAL dictator who no-one wants to cross even more than usual.
Oh, and I'd get my scientists to work hard on developing biological immortality. It's more fun to rule an empire when you're suffix is "the Undying".