The Boy Scout slogan
. Different than the Boy Scout motto
, Be Prepared
! to "do a good turn daily" meant to do something positive
, at least once
to offset all the awful shit
you did the rest of the day. This is embodied in popular culture
by the image of helping a little old lady across the street
It probably didn't mean anything you would do while driving, since most Boy Scouts are not of legal driving age.
It surely does not mean "turn a good trick daily." That's something else entirely.