A crane operator should always move loads according to the established code of signals, and use a signaler.
Hand signals are preferred and commonly used.
With forearm vertical, forefinger pointing up, move the hand in a small horizontal circle. Regular signals follow. Palm up, fingers closed, thumb pointing in direction of motion, jerk the hand horizontally. Arm extended, palm down, hold the position rigidly. Arm extended, palm down, move the hand rapidly right and left.