I use grease.
I forget the name, but it is gun specific. It comes in a plunger type applicator and is a VERY thick red grease.
After cleaning I give everything a light coating of spray oil, then wipe it all down.
Then I use a toothpick and apply the grease (NOT sparingly) to the rails on the frame, the grooves in the slide, under the slide where it glides over the hammer, the hammer, under the trigger bar, and I think that is about it.
After all of that, I run the slide back and forth several times on the frame, assemble, and run snap caps through at least a dozen times to ensure function as best I can without actually firing.