The center belongs to more winning lines
Outer discs belong to fewer four-cell horizontal segments. The center connects in both directions and participates in more diagonals, so early central control preserves more plans.
This is not an automatic move rule. Block an immediate opposing win first. Central control is a long-term advantage considered only after urgent tactics.
Every disc supports the next one
A winning cell in mid-air is not yet an immediate threat. It becomes playable only with support below. A careless defensive drop may build the missing support for your opponent.
Before every move inspect the next level in that column. If it gives the opponent an immediate win, find another defense or create a forcing threat of your own.
Create two playable winning cells
A double threat offers wins in two different columns next turn. One opposing disc can occupy only one. A shared disc between a horizontal and diagonal plan often prepares this position.
Look beyond visible rows of three. Consider moves that support two future endpoints. A real trap still works after the opponent chooses the strongest reply.
Review losses from the first unavoidable position
The final winning disc is often impossible to block. The actual mistake came earlier, when the opponent could build two threats or force a support cell. Step backwards from that position after a game.
Against the computer, pause at critical turns and imagine its strongest reply. A plan that succeeds only after a cooperative response is not a sound tactic.