Careful, prudent, cautious.
Sounding as if it is coming through a tin can.
Frugal, thrifty.
Friendly, pleasant, fair, agreeable; (sometimes) funny.
Gentle, quiet, steady.
Knowing, shrewd, astute.
Gently, quietly; carefully, skilfully.
Very, considerably; quite, rather.
Carefully designed or arranged, with plenty of forethought, so that it functions satisfactorily.