The one who blows the Shofar (Ba'al Tokei’a) should be a righteous and learned person. He should review the Halachic and (if possible) the Kabbalistic aspects of blowing the Shofar beforehand (see below).
In addition, the Ba'al Makri (the one who points [or reads] to the Ba'al Tokei’a as to what sound to blow) should be a righteous man who is fluent in the laws and meanings of the blowing of the Shofar.