Removing any toolmarks from the engagement surface of the sear helps. As does possible adjustment of the relief cut on the sear. Possibly adjusting the sear spring tension, but that's not something you can teach in books. Deburring the trigger, trigger bar and sides of hammer & sear can also help with smoothness. As does polishing the inside of the mainspring cup.
Due to the design of the hammer hook on the S&W autos, the best advice I can give is to leave them alone. Wolff does offer spring kits, if you're using this for defensive purposes, I'd be very careful about using anyone's spring kit.
The same general practices apply to most all of the auto pistols, with some minor changes due to differences in design. I'd try deburring with a very light touch of a soft Arkansas stone on the top of the sear if you can do so without changing any angles.
OR, given your location, Call Rick Devoid at Tarnhelm Police Supply or Gunsmithing. He's very near Concord. He does excellent work.
