Five rules with consistent research support.

1. Repair quickly. Speed of repair after conflict predicts durability more than conflict frequency.
2. Maintain 5:1 positive-to-negative ratio. Gottman's finding across decades.
3. Accept influence from each other. Rigid "I'm right" stances correlate with dissolution.
4. Turn toward bids for connection. Small moments are the actual test.
5. Keep curious about each other. Long relationships stay warm when both people keep noticing.

Five rules. Practise the first two for three months; the relationship improves measurably.