I was wondering what are some of the more popular mods we make on our Glocks. I've found one big thing that makes me a better shooter with mine is the Ghost Rocket connector. This is a lighter pull (3.5# or 5#) but the big advantage for me is that it has a trigger stop that ends that atrocious over travel when the trigger breaks. This keeps me from shoving my trigger finger into the natural stop at the end of trigger travel and steering (jerking) the sights off target. Maybe I just never fully adapted to the Glock trigger pull so need this help. Differences are apparent with the guns when I dry fire and groups with fast fire are about half of before.
The thing takes some fitting but that is just a good opportunity to learn more about the lock-work of these simple beasts. I also change the recoil spring guide (and usually the spring) from plastic to steel or titanium.
I do like the standard Glock extended slide release and magazine release buttons, not the various aftermarket parts. I do a lot of the GSSF shoots where two mag changes or the norm for most scenarios and those parts work well for me with my medium sized hands and the 9mm/40 size frames and the SF in the larger framed Glocks.
I also want steel sights on all my pistols so the cheap plastic has to go, usually for tritium dots or higher vis of some type depending on the primary use.
A lot of folks seem to want a better barrel but I haven't found that to be much help for me and usually stay with the standard.
And of course I like to polish the internal lock-work parts such as the striker lip, the trigger bar and connector and the firing pin safety button.