5 ideas
Direct your forces toward the point where the opponent is weakest, and bring more attackers to bear on that point than the defender can muster defenders. Superiority at a single decisive point, not general advantage across the board, is what converts position into victory.
A position contains an underlying balance of small advantages (space, pawn structure, piece activity), and a player may only attack when they possess enough accumulated advantage to justify it. Attacking from a balanced or inferior position invites refutation, so one must first accumulate small permanent gains before striking.
Positional play means gathering minor, often permanent advantages such as better pawn structure, a stronger outpost, or superior piece mobility, rather than seeking an immediate knockout. Only when these small edges add up to a clear superiority does a concrete combination become sound. The combination is the harvest of positional work, not a substitute for it.
Lasker argues that memorizing opening lines and specific moves produces brittle skill that fails once the opponent deviates. Understanding the reasoning behind moves, such as development, the center, and the relative value and function of pieces, lets a player generate good moves in unfamiliar positions. Judgment built from principles transfers to new situations, while rote knowledge does not.
In Steinitz's theory as Lasker presents it, a player holding an advantage must attack, or the advantage dissipates. A player without one should not attack, because an unjustified attack weakens the attacker's own position. The balance of the position, not temperament or ambition, decides whether aggression is correct.