Generally speaking, the smaller the continent, the better it is. Small continents are easier to capture and defend. However, not all of these continents are necessarily a good choice. Small continents can have limited access to the rest of the world and tend to be isolated. Indeed, some people prefer to stay isolated initially until they feel strong enough to suddenly emerge all powerful and conquering. This dream however may die quickly as you will discover that an isolated power could be at the mercy of more resourceful and politically driven empires.
The best example for an isolated continent is Australia. It has only one border with the rest of the world (less than all the other continents) and practically impossible to conquer in the early game once somebody has claimed it. It is usually highly desired. This is good news. However, there is also a trade off. The problem with Australia is that there is no place to expand to. Usually the player in Australia lasts through the game to the end since Australia feels like a fortress to other players. Over time, however, the player falls behind as other players collect larger bonuses than him. Being isolated, he usually does not participate in world politics either. Before long, he is
eaten up by the few remaining superpowers of the game! In short, Australia is a double edged sword, be careful how you use it.
Machiavelli argued that in a strictly military sense, a fortress is invariably a mistake. It becomes the symbol of a power’s isolation and everyone will know where to attack. The fortress may appear to be unconquerable but it will be restrictive. Its isolation provides no protection and actually creates more problems than it solves. To make yourself powerful, you must place yourself at the centre of things. All activity should revolve around you and you should be aware of everything that goes on in the environment.
Remember, that there is an alternative to
continents-first strategy. You can use territories-first strategy instead. In this method, your intension is not to go for a continent first. Instead you should get as many territories as possible, preferably connected. Notice that by taking six territories anywhere, you will get the same bonus as Australia or South America. The idea is that if you play for a continent, you will end up playing defensively as you want to protect your continent. In practice, if you can own 18 connected territories anywhere on the world map, then you are better off than owing North America without a couple of territories left to conquer. Of course, later in the game you need to start focusing on continents as well as they cannot be ignored in the long term. It is your decision to select between these strategies which highly depend on your position on the map, your opponents, order of play and your style.
In any case, in the beginning of the game, you need to know exactly what your overall strategy is. This is critical. Establish which continents or territories you prefer to own and once you are in a particular continent or area, what type of players you are likely to encounter. Your move must always consider the psychological profile of each player. If you want to win, you have to use every trick of the trade at your disposal.