Winning strategy: If you start in the middle of a large landmass restart your game until your on an island or right next to one. Next take over the territories immediately surrounding you (depending on where you start this may mean a whole continent) until you've made it so that the enemy can only get to you through three or four territory's. Next use on of these "gateway" territories to evade the smallest accessible land mass (remember islands are your friends) and use your spare armies to beef up your other gateway countries. Once you have two fairly secure groups of territories under your control try to expand around the edges of the map. Going for the center of a large number of territories will only get you killed. If you're careful and advance with caution you'll be able to surround the huge land masses on all sides then you can move in for the kill.
This game really sticks out from other similar games on kongregate because the game actually makes you think about every move because to win you have to have a perfect balance of offense and defense. Move to fast and you'll be stretched out defending ten territory's at once. Move to slow and you'll get outnumbered ten to one. Great game I wish there were more like it.