How do I mortify indwelling sin?

My response to Chapter 3 of Overcoming Sin and Temptation, which is entitled "The Holy Spirit is the Great Sovereign Cause of the Mortification of Indwelling Sin."  One of my favorite quotations from this chapter is this one:  "In a word, they [Roman Catholics - or any of us, by nature!] have sundry means to mortify the natural man, as to the natural life here we lead; none to mortify lust or corruption.  Search their ways and principles to the bottom, and you will find that it had no other root but this mistake, namely, that attempting rigid mortification, they fell upon the natural man instead of the corrupt old man—upon the body wherein we live instead of the body of death."