When making a mistake, do not be afraid to correct it. Be quick to amend one's wrongs.

to err, to blunder, to commit a mistake / (in the conjunctive ～て form) negligently

always

endeavor, strive for, make an effort

betterment, improvement, amelioration

to chop, mince / to carve, to cut / to tick away, to keep time

(transitive) to improve, to make better / (intransitive) for something to improve on its own

improvement, an action taken to improve / improvement, a spontaneous change for the better

must not, do not, be not

negation / prohibition