Step one is the owner's manual... it will explain what is adjustable and how to do it. With most recent (the last 10 years or so) production rifles, they have "lawyer triggers" with a heavy, non-adjustable pull. The overtravel stop is usually the only adjustment.
The new Savage adjustable trigger is supposed to be pretty slick, but is only available on new Savage rifles. For an A-bolt, if your factory trigger isn't adjustable, I'd look into an aftermarket trigger such as a Timney. Unless you REALLY know what you're doing, don't mess with the trigger - I've seen the results of unqualified tinkering, and they aren't pretty (50-50 odds that the gun fires when the bolt is closed, a safety that doesn't work, or a rifle that fires when the safety is clicked off).
The new Savage adjustable trigger is supposed to be pretty slick, but is only available on new Savage rifles. For an A-bolt, if your factory trigger isn't adjustable, I'd look into an aftermarket trigger such as a Timney. Unless you REALLY know what you're doing, don't mess with the trigger - I've seen the results of unqualified tinkering, and they aren't pretty (50-50 odds that the gun fires when the bolt is closed, a safety that doesn't work, or a rifle that fires when the safety is clicked off).