Well, the first thing you need, is money. Lots of money. Starting a new life in foreign country is not easy. You need rent, food, deposits, this and that.
and the most important thing, a job. And getting one decent one wont be that easy.
But i think the most important thing is that whether that country you are migrating to have a demand on people like you. For example, lots of American moved to Korea to be English teachers because Korea have a large demand of native English speakers.