The winner of the game is the person who is most effective at using their influence cards to gain power, which makes more power, and power gains more power…. You get the idea.
You basically have three areas a turn to spend your cards: Development (also to get new defensive technologies), Foreign Influence, and Conflict. The basic problem is that if you spend the cards in the earlier offensive phases to increase your power and technology (which aids in defense), you don’t have any defensive protection if someone attacks you.
Here are some other points to remember:
Keep an eye on the Imperial player. They get a great advantage of being able to influence level one independent without paying the distance penalty. With this power, then can capture small countries quickly and develop them up to a level two. If you start to see the Imperial player run away with points, get the other players to chip away at him.
If your opponents are not saving their cards for the conflict phase, attack their home country if you don’t have a distance penalty and have the advantage. If you win, during the next foreign phase, remove your influence card. This will cause them to go down a point for the turn and cannot be fixed until next round. But don’t go crazy with attacks. Just do a few to keep them on their toes and make them hold cards back. It’s kinda like boxing in a way.