Here are two of the things I have learned about adjusting trigger pulls:
1. Do you have a rough pull? Heavier than you would like? Want to make it better?
The first thing you should look at is the entire system--everything that moves when you pull the trigger EXCEPT the sear/hammer relationship. It's really comparable to tolerance stacking. How?
Let's take the 1911 pistol. Where are the contact points? The trigger stirrup/frame relationship, the stirrup/magazine relationship, the fit of thesear inside the frame, the fit of the hammer inside the frame, the fit of the pins (yes, the pins) for both the hammer and sear.
How about the contact points for a S&W revolver? The trigger to frame fit, the rebound slide/frame fit, the hammer and trigger pin/boss fitting, the hand/window fit, and the trigger/ DA fly fit. Don't forget the inside of the rebound slide, either--where the rebound spring goes.
Where pins are concerned that are integral to the frame, it's best to simply coat them with light grease or oil, and dry fire. Nothing smooths as evenly as the contact surface itself. Polish the large surfaces with a smooth ceramic stone and oil. Do NOT try to achieve a mirror surface. The heat treatment on these parts is only a few ten-thousandths of an inch thick. Polishing the parts will break through the heat treatment.
2. Before you go changing sear angles, change the springs. For instance, simply installing a different mainspring and rebound spring will do wonders for your Smith and Wesson. I recommend the Power Custom mainspring. Use only a full, unaltered strain screw. Also, change out the rebound spring; I prefer a 13" spring here. On a Smith and Wesson revolver, I learned the hard way: NEVER touch the sear nose/hammer notch. They're almost nonexistent to begin with.