The initial selection of the territories is critical. You want to claim a variety of resources, while at the same time establish a connected set of territories that you can readily protect. One tactic is to make your first few selections such that a larger group of territories are inferred to be in your control. When done properly, this can allow you to effectively control more than your share of the continent. If you are too aggressive, however, your territories will be too centrally located to easily defend.
Borderlands revolves around the proper management of the resources.
Resource tokens are produced in the player's territories. If the appropriate tokens are assembled in the same territory, they can be exchanged for development tokens. For example, a Weapon, which is useful for attacking, can be produced from either a Coal and an Iron or from two Gold resource tokens. In addition, the first player to occupy three territories with Cities at the end of a turn wins the game. Ultimately, Borderlands comes down to acquiring the right resources, maneuvering them properly, and exchanging them for the most useful developments.