The invention relates to a method for visually assisting the alignment of a medical instrument, wherein the instrument is visually displayed on an image output in a positional relationship to a part of a patient's body by means of a medical navigation system, wherein an orientation aid is displayed as a virtual model shape at the instrument or in a particular positioning with respect to a characteristic part of the instrument. It also relates to a planning method for optimized instrument alignment with the aid of such an image assisting method.