This is a long one but I won't be posting for a while so read at your leisure...
1) This is the occasion for change not the reason for change.
It's great if you've come to some sort of crisis moment. It's good that you want to change. But you ought to know that this is the struggle of your life.
I don't mean: This is the struggle of your life. I mean: This is the struggle of your life. Welcome.
2) If you're not struggling, you're losing. Or worse, you're not even a Christian.
Christians struggle. We are the product of two births. Our flesh is from Adam, our Spirit from Christ. If you're not struggling then you're simply gratifying the cravings of your flesh (however respectable you may look). And perhaps you don't even have the Spirit. Let the comfortable be disturbed. And let the strugglers be comforted - your battle is a sign of the Spirit's work.
3) If you are struggling, you have a Power within you to live new creation life.
If Christ is in you, you have the power that called forth the universe and He is determined to bring supernatural change. Mark 4 comes to mind - the power of Christ's word can and will produce 30, 60, 100-fold growth but of course it will be as gradual and organic as the growth of a seed. Nonetheless this is what you are aiming for - not simply the correction of some annoying habits but the transformation of your character through Christ's word. Be encouraged by your struggle - it means that an other-worldly Power is at work and will transform you in ways you can only begin to imagine.
4) Your righteousness is entirely outside and above you.
These problems do not define you. Your success at handling these problems does not define you. Christ defines you. We don't say 'My name's Glen and I'm an alcoholic' (or insert your problem of choice). We say 'My name's Glen and I'm a saint clothed in Christ... I also happen to struggle with...' We don't struggle for but struggle from freedom.
5) You must deal with this struggle in community
All the real action happens outside of you. You need the word of life to come from outside. As Bonhoeffer says 'The Christ in the word of a brother is stronger than the Christ in my heart.' At the same time you need to put words to your darkness and, again, bring it outside. Sin thrives in the dark, you must bring it into the light. 1 John 1:5-10. James 5:16. Find someone.
6) The person you reveal yourself to be in the midst of these sins is the person you've always been.
We tend to think that we're generally righteous and these problems have been a blip. David knew better. When he committed adultery and murder he realised that this was the person he'd been 'from birth - sinful from the time my mother conceived me.' (Ps 51:5) These problems are just you with the hand-brake off. Ugly huh?
But know also...
7) The person you reveal yourself to be in the midst of these sins is the person Jesus loves and has forgiven.
Jesus did not die for 'me-on-my-best-behaviour'. 'While we were still sinners Christ died for us' (Rom 5:8). 'God justifies the wicked' (Rom 4:5). Which 'me' does Jesus love? The cleaned up me? No. Jesus loves the me I showed myself to be in my worst moments. When we grasp that Jesus is committed to us even and especially as we stink of sin it's a hundred times worse but a thousand times better. We must grasp the depths of this love for me the sinner - this is fundamental to real change.
8) With 4-7 in place - you can learn to hate and hope appropriately.
Focussed in on ourselves we tend either to lose hatred or hope. Either we don't really hate our sin because we're too attached to the 'me' who committed it. Or we don't really hope for transformation because we can't imagine such a 'me' changing. The problem is that we're too attached to 'me'. Number 4) is the truth that releases us from that attachment and number 5) is the practice of it. We then learn how to address this 'me' the way we'd address a brother or sister in sin. As another addresses you in your sin with appropriate hatred and hope, learn to see things from this much healthier perspective.
9) Your problems are really your 'solutions'.
You'll be tempted to think...
"I have a recurring personal problem with X."
Don't be so sure. Probably the truth is something much closer to...
"X is my solution to its insufferable alternative - Y"
X is a chosen strategy to avoid what you consistently reckon to be an even worse state of affairs. You need to be thinking about what is Y, and why Y is so unbearable that you'd choose X. Your deep fears (of Y) may be completely irrational and out of control. But your chosen strategy, X, is not.
10) Even the most seemingly compulsive and irrational 'personal problems' (non-organically caused) are, on deeper examination, chosen and intended strategies.
It might take some digging (Prov 20:5), but you will find volition at play. This ought to reinforce the hope and hatred mix. Hope because you're not bound to sin like this. Hatred because you've consistently and deliberately chosen these sins in defiance of Jesus and His way.
11) Until you've diagnosed your problem as one for which Christ is necessary, you haven't defined your real problem.
Your problem is not low self esteem or negative thoughts or panic attacks or over-eating or self-harm etc etc. None of those require the blood of God. Until you do the hard work on 4-7 and get to the heart issues - your angry defiance of your Father, your petrified mistrust of Christ, your obdurate resistance of the Spirit - you're treating your wound lightly.
Jesus had to die. Divine wisdom and heavenly encouragement have never been enough to address the human problem. You don't just need a bible study and a pep talk. You need bloody, wrath-bearing atonement on your behalf, while all you can do is watch aghast. Until you see your problems in that light you won't be appropriately humbled and all your efforts at change will be a re-arranging of the flesh.
12) Until you've set your hopes on a change for which Christ is necessary, you're not aiming for Christian growth.
It's tempting to aim for a re-arranging of the flesh. For instance, you may struggle with pornography and therefore make your resolution to be porn free from now on. Well, ok. But Ephesians 3 tells you that resurrection power is available to effect in you far above all you can ask or imagine (Eph 1:19-20; 3:20). To aim for a clean internet history is not really to aim for Christian growth. To aim for a pure heart that knows God and a burning zeal for Christ that takes you out of yourself and into the world - that's your prayer. And it's impossible. You can't do it. Only resurrection Power can. But that's where you aim if you want Christian growth. And kicking pornography is just a little part of that.
Putting 11) and 12) together you get this:
Christ's cross tells you to dig deeper,
Christ's resurrection tells you to reach higher.
The cross drives us down so that we call out in desperation, the resurrection lifts us up so that we ask for that which is humanly impossible. There is therefore a gospel shape as well as a gospel power to our prayers. Perhaps use the Lord's Prayer as your guide. Every line of the prayer calls us to change. Don't move on in the prayer until you've prayed through the issues that each line is raising. Here is the really hard work of change, but only because it's so powerful.
14) In your desire to change there will be both flesh and Spirit at work.
Your flesh wants you to change to gain control, look better, escape guilt feelings, avoid the need for dependence, achieve a righteousness of your own, etc, etc. Bring these false motives before the Lord and repent of your repentance strategies. True repentance comes from a brokenness that realizes even our tears of regret need washing in Christ's blood.
At the same time be aware that there is a true yearning from your new nature - a deeper desire to know Christ and be conformed to His image. Get in touch with the Spirit's stirrings here through prayer and conversation with others. Figuring out why you want to change and having this answer come from the right place is priceless.
14) Address your entitlement spirit?
The flesh is ever desiring to establish its own righteousness. How, specifically, are you seeking to make a name for yourself? According to your flesh - what are you trying to earn? What do you feel you are owed? What do you have to do to earn this? What has blocked your goals? Having thought about this, try to articulate the shape of your entitlement spirit. How does the gospel address your entitlement spirit in general? Specifically, how does the gospel address the specifics of your entitlement spirit? Real change is happening when the Gospel demolishes your flesh-strategies.
15) You already have the solution
Not within you! In Christ.
4Remain in me, and I will remain in you. No branch can bear fruit by itself; it must remain in the vine. Neither can you bear fruit unless you remain in me.
5"I am the vine; you are the branches. If a man remains in me and I in him, he will bear much fruit; apart from me you can do nothing. 6If anyone does not remain in me, he is like a branch that is thrown away and withers; such branches are picked up, thrown into the fire and burned. 7If you remain in me and my words remain in you, ask whatever you wish, and it will be given you. 8This is to my Father's glory, that you bear much fruit, showing yourselves to be my disciples.
9"As the Father has loved me, so have I loved you. Now remain in my love. (John 15:4-9)
Allow these words to live in you and allow yourself to live in Christ.
16) Some or all of these things are true of you:
You have little joy, take yourself too seriously, don't have the friendships you need and are not sleeping/eating/exercising as you should.