How can I replace a standard light switch with a dimmer switch?

To replace a standard light switch with a dimmer switch, first turn off the power to the switch at the circuit breaker. Remove the cover plate and unscrew the switch from the wall. Disconnect the wires from the old switch and connect them to the dimmer switch according to the manufacturer's instructions. Screw the dimmer switch into place, replace the cover plate, and turn the power back on to test the dimmer switch.