It is tempting to read the New Testament as if most of what it says is meant for someone other than me--maybe somebody who is just a better person in some sense, or someone who has figured out some elusive secret to transformation that I just haven't stumbled on yet. There are times when I just feel like my life will never and can never look like that.
I think this is harmful for spiritual growth. If you don't believe that God is interested in and capable of actually transforming your life--cultivating in you genuinely new and healthy patterns of thought and action and so overcoming sin and growing you into maturity--then you will be always already discouraged. It is incredibly burdensome to live out each day mentally assenting to things you're unable to consistently carry out in practice.
If you resonate with that feeling, I suggest two things. First--and this is foundational--you need to refocus on how shockingly profligate and utterly counterintuitive grace is. Grace is God's absolutely undeserved blessing and favor; it is a gift that cannot be earned or deserved and, for that matter, cannot be unearned or lost, for the same reasons. It is freely given and freely received. A good practice for remembering this is to read something like Yancey's What's So Amazing About Grace, or Manning's The Ragamuffin Gospel. They will consistently redirect you to the simplicity and power of Jesus' parables of the kingdom that illustrate just how God treats those who could never deserve it; to the theological riches of the great Reformation insight about justification by grace through faith; to the biblical picture of a God whose love is so relentless that he gave up his Son, who forgave even those who murdered him.
Second, I suggest reorienting yourself to the fact that the New Testament everywhere presupposes the reality and availability of personal transformation. Sometimes we forget this because we don't read the Bible very much, or we read it in small bits and pieces and don't see people painting the big picture, or when we do read we're not sure what to look for. But I am convinced that the New Testament assumes, as a matter of bedrock confidence, both that those who are in Christ are completely new (regardless of how this looks or feels in an individual life) and that an important part of this newness is the possibility of actually growing into maturity and living differently. This is not so much obligation as it is hope: Come and see the new kind of life that is actually possible! You don't have to feel beat-up and worn down and guilty! You can let those things go and be formed in the image of Christ!
To help make this point, I've gathered here a bunch of Scripture passages that I think - especially when read side-by-side - can lead you to no conclusion but that such a life really and truly is available. The reason I focused on grace first was that spiritual transformation always takes place in a context of grace, so that you can never mistake what you're doing for earning God's favor, and so that you won't do things out of fear. There is only hope and love. But as you cement this in your mind, you can then realize that grace is not passive: it is active and transformative. As Dallas Willard likes to say: "Grace is opposed to earning, not to effort."
And I am well aware of the danger of stringing together multiple passages of Scripture without examining their contexts; but trust me when I say that the contexts of these passages only strengthen my point. Or you could be responsible and look them up yourself.
1 Peter 1:13-16
2 Peter 1:3-11