Greet everyone ‘b’seiva panim yafos’ (Avos), see it as a Mitzva you have to do, this will automatically make you outward going.
Someone asked a Baalie Mussar ‘should he study all the mussar books to change his personality for the better, he answered all you have to do is keep all the 613 mitzvos, and not break the 218 aveiros, if you do that, your personality will automatically change.