The sharp edges don't need a lot of reducing to give a comfortable feel.
There are two main methods, made easier if you can remove the trigger from the gun. But it can be done assembled.........
Use a Dremel tool with a Cratex rubber Medium grit abrasive cone to smooth the areas.
Wrap fine wet or dry sand cloth around a wood dowel and use it like a file to break the sharpness.
If you do either with the trigger in the gun, wrap LOTS of masking tape around the frame and inside the trigger guard. Wrap EVERYTHING that might be hit if you slip.
Make sure all opening into the action around the trigger are covered to prevent abrasive grit from getting into the action.
Tape is cheap, USE PLENTY.
Brownell's sell the rubber abrasive cones and mandrel, and Dremel sells mandrels in many hobby and hardware stores.