Options to improve actual or potential accuracy:
Actual accuracy is a change that improves the mechanical accuracy, ie ammunition that is capable of smaller groups.
Potential accuracy means a change that allows the shooter to shoot better groups, ie better sights that allow the shooter to shoot better.
Better trigger pull.
"Possibly" using a milled rather than a stamped receiver. (While no guarantee, milled receivers do have a better track record for accuracy).
A more accurate cartridge. The AK round is tapered to improve feed and extraction at the cost of some potential accuracy.
While there are some accuracy rifle techniques that might improve things, such as squaring up the bolt face, these will have limited effect due to the AK design.
Bottom line is, the AK was intended to be an "assault rifle" and reliability was considered paramount. It was never intended to be an accuracy rifle, and in fact Kalashnikov deliberately reduced accuracy-improving fit to improve function.