做

Person radical on the left — the side-form of 人. Indexes 做 in the human-action family with 你, 他, 们, 作, 住. Marks 做 as something a person actively does — making, doing, performing. The radical pins the verb to a human agent, distinguishing 做 from passive 成 'become.'

Right side 故 supplies the sound (gù → zuò, an old k-/ts- alternation that has obscured the link). 故 itself is 古 'old' + 攵 'rapping hand' — the picture of doing something with reasoned cause. That 'cause and effect' sense fits 做 well: doing = bringing about, acting deliberately. Same root family includes 作 'to do.'