The only things I did to my carry gun, which is a Glock 26, was put on night sights(I went with XS 24/7), extended slide lock, pierce mag extension and titanium safety plunger. The two last and most important things were a good holster (crossbreed supertuck), and tons and tons of ammo. On a carry gun I wouldn't recommend doing too much. And like Quentin said, shoot it as is for a while, you may find that you don't want to change anything.
"Breathe when you can, shoot when you should."
"Qui desiderat pacem, bellum praeparat; nemo provocare ne offendere audet quem intelliget superiorem esse pugnaturem"