Holy is a state of being within your soul that is manifested by the behavior of your will and body.
You achieve this state of being for your soul by immersing yourself in the desires of GOD, i.e. study HIS Bible, believe in HIS SON, participate in Prayer and the Sacraments, defend the Faith, Evangelize as needed, emmulate saints and their practices and prayers etc. - and the longer you stay immersed and the deeper you delve into attempting to understand and pursue the desires of GOD, then you begin to reflect GOD in your will and body, which is to say your speech, attitude and behavior.
Therefore, being Holy is being a reflection of GOD to others in such a way that others notice and realize that you are truly “different” than most, i.e. kinder, gentler, more considerate and concerned.