Grease trigger pin and sear pins; polish too if you want. You can polish (very lightly) trigger pin holes, disconnector pin holes, and sear pin holes.
The primary points of interplay/friction on the trigger are disconnector to sear and striker to sear. Definitely lubricate, but you can also polish these surfaces as well.
Lastly would be springs, trigger leaf springs and disconnector springs being only ones relevant here. The lighter they become the more likely you are to introduce the gremlin if your carrier isn't tabbed, etc.
Anytime you mess with the trigger there's the potential to make your weapon unsafe, so do so conservatively and at your own risk. And thoroughly test your weapon after any modifications with stuff like triggers before you put live ammo in the gun...
Good luck, let us know your results.
