I have power coming from the panel, running up to the front of my garage to the first light, from there to the second light and from there to the switch.
My first light stays on all the time, but the second light will turn off and on by the switch.
I am using 12-2 with a 20 amp breaker
How do I correct this so both lights work off the switch?

Unless you can revise the wiring and either run from the panel to the switch first or from the panel to the second light first, you will need 12/3 between the 2 lights. Apparently the hot from the panel is presently connected directly to the first light, then switched at the second light. The hot from the panel has to travel (bypassing both lights) to the switch, then the conductor that is energized when the switch is on, must make it back to the both lights, which requires the 3rd wire between the lights.

Unless you can revise the wiring and either run from the panel to the switch first or from the panel to the second light first, you will need 12/3 between the 2 lights. Apparently the hot from the panel is presently connected directly to the first light, then switched at the second light. The hot from the panel has to travel (bypassing both lights) to the switch, then the conductor that is energized when the switch is on, must make it back to the both lights, which requires the 3rd wire between the lights.

Thank you!

In the 1st light box u should have 3 cables. One from the switch, one from the power and one from 2nd light.

Connect black wire from power to black wire from switch.

Connect white wire from switch to 1st light with a pig tail and to the black with from 2nd light. Mark the white wire with black tape at both ends to show it is hot.

Connect white wire from power to 1st light with a pig tail and to the white wire from the 2nd light.

Should be good to go.

Chuck