I have played many a World Map game. If you have country questions in particular, I can help you, but Captain got is mostly right. Usually, neighbors attack neighbors first. In North America, one power is eliminated and then usually a truce is called. South America can usually count on a truce between Brazil and Argentina, as it is by far the easiest continent for an outsider to invade imo (North America invading south beats South American invading north probably 75% of the time). Africa usually sees the elimination of two powers, Europe usually doesn't do much, pushes into North Africa, is overrun by Russia. In Asia you usually see two powers fall fast (counting Russia and Near East as Asia). Oz and F-A almost always knock the other one out to start off. Sea spaces are the most important ones on this map.
You need to fleet up as fast as you can in order to keep your territory for phase 2, which is continent scale invasions. The best way to protect yourself? If in the northern hemisphere, grab at the North Pole. If you control the Northern Ocean, then you are very safe and can expand into Asia or North America with ease. If you're in the southern hemisphere, you need to have a solid presence in Antarctica. If you're in the middle? Then try to grab control of as much of a continent as you can and seal up the tiny sea spaces (Med Sea, Red Sea, Caribbean and Gulf of Mexico) as well as the most important ones (EAO, NWA)