What two actions were taken to avoid a return to the brink of a nuclear war in 1963?

In addition to the above accurate results from the Cuban
Missile Crisis, the United States pledged not to try and invade Cuba, virtually
guaranteeing its continued existence as a communist state under Fidel Castro.  This was
a reversal of a three year effort by the CIA to either assassinate Castro or to
overthrow his government.

The US also removed missiles it
had secretly installed in Turkey, on the border of the Soviet Union, and a direct line
of communication was installed between Moscow's Kremlin and the White House so that an
accidental nuclear war was less likely.

It's clear from
these actions, as well as the Test Ban Treaty, that both the Soviet Union and the United
States understood how close Armageddon had come to being
reality.