Whatever you do don't let anybody talk you into a shadetree modification of anything. I haven't seen any thing like the number of catastrophic failures with anything else so much as I have with AR triggers that have been f'd with.
LOL This would be a lot more funny if it weren't so true!
Biggest problem people make is they get a little overzealous with their sanding/polishing of the trigger sear and round it off which typically causes the gun to double, or, sometimes worse.
Unless I'm working on a trigger that has some realllly nasty machine marks I never use anything courser than wet/dry 600 followed by 1000 then 1500. I'll usually finish with a buffing wheel and a drop of Flitz and it'll look like it was hard chromed when I'm done.
One of the most important things to remember is a little goes a long ways and keeping the angles the same and the face square.
For the most part, polishing up the contact surfaces just makes the creep/pretravel smooth instead of being so critty and crunchy feeling. You typically aren't going to lower the pull rate very much by only polishing an AR trigger.
You can significantly improve the overall trigger by polishing AND replacing the springs with a set from someone like JP Enterprises. The very first AR15 I ever bought was an old triangle forearm heavy barrel Olympic Arms I bought wayyyyy back in 1985 and not only was the trigger pull 9lbs but it felt like two boulders rubbing together while you were pulling it through its mile of pretravel. To say it was really bad is putting it mildly. Awhile back I was bored so I went and dug it out and was curious to see how much, if at all, I could improve the trigger. I had an extra set of lightened trigger springs as well as a grip screw trigger adjuster. A little work polishing, $25 in parts, and it's now a consistent 3.25lb trigger with nearly no creep. My CMC triggers are definitely better but they cost $150 too.
FWIW, I've even used the reduced rate springs in a M&P 15-22 with no issues so it's not like they'll cause light strikes if that is a concern.