There are four 'marcro' items that you can adjust in order to improve accuracy. they are:
Action Bedding in high quality/decent stock
Blueprinting/truing action or lapping bolt lugs
Replace barrel/recrown existing barrel
Difficult to say how much any of these will improve accuracy. the only way to know would be to make one change at a time, then remeasure accuracy.
I can say that if you do all or most of these, your rifle is almost guaranteed to improve:
Nephew's Transformed Rifle!