3 ideas
The king must first conquer his own senses and vices — hunting, gambling, women, drink, harsh speech, harsh punishment — because unchecked appetites corrupt judgment and drain the treasury and army from within. A ruler who cannot govern himself will lose the loyalty of subjects and ministers regardless of external strength, so discipline of the self is the foundation on which every other element of power rests.
A would-be conqueror maps surrounding kingdoms by position: the immediate neighbor is the natural enemy, the neighbor's neighbor is the natural ally, with further rings of the enemy's ally, the ally's ally, a middle power, and a neutral power beyond. Foreign policy is then calculated from these geographic relationships rather than from sentiment, since shared borders create conflicting interests and distant powers share an enemy.
The state is treated as an organism of seven limbs — sovereign, ministers, territory with its people, fortifications, treasury, army, and allies — each supporting the others. Strength is assessed by examining each limb for weakness, because a calamity to any one, especially those nearer the top of the list, cripples the whole, and war or peace should be chosen by comparing one's own limbs against the enemy's.