Sinclair Ferguson writes a helpful article on “Killing Sin” at this link.  He examines Colossians 3:1-17 and makes 4 practical points of application:

1. Learn to admit sin for what it really is. Call a spade a spade — call it “sexual immorality,” not “I’m being tempted a little”; call it “impurity,” not “I’m struggling with my thought life”; call it “evil desire, which is idolatry,” not “I think I need to order my priorities a bit better.” This pattern runs right through this whole section. How powerfully this unmasks self-deceit — and helps us to unmask sin lurking in the hidden corners of
our hearts!  

2. See sin for what your sin really is in God’s presence. “On account of these the wrath of God is coming” (3:6). The masters of the spiritual life spoke of dragging our lusts (kicking and screaming, though they be) to the cross, to a wrath-bearing Christ. My sin leads to — not lasting pleasure — but holy divine displeasure. See the true nature of your sin in the light of its punishment. Too easily do we think that sin is less serious in Christians than it is in non-believers: “It’s forgiven, isn’t it?” Not if we continue in it (1 John 3:9)! Take a heaven’s-eye view of sin and feel the shame of that in which you once walked (Col. 3:7; see also Rom. 6:21).

3. Recognize the inconsistency of your sin. You put off the “old man,” and have put on the “new man” (3:9–10). You are no longer the “old man.” The identity you had “in Adam” is gone. The old man was “crucified with him [Christ] in order that the body of sin [probably “life in the body dominated by sin”] might be brought to nothing, so that we would no longer be enslaved to sin” (Rom. 6:6). New men live new lives. Anything less than this is a contradiction of who I am “in Christ.”

4. Put sin to death (Col. 3:5). It is as “simple” as that. Refuse it, starve it, and reject it. You cannot “mortify” sin without the pain of the kill. There is no other way!