The short answer is we can't, at least on our own. That's the problem with the Fall - we fell in our entire nature right down to our core, so there is no place we can fall back on from which to pull ourselves up. Any attempt we make is doomed to fail because the attempt can only come from fallen nature, and so is already affected by the problem it is trying to cure. That's why our attempts to find a way to live always have a ring of artificiality to them. They must, because we are trying to construct a way to live from degraded blueprints and with degraded carpenters.
The only answer is for someone to save us - which, of course, God has accomplished in the Incarnation. Christ shows us what it really means to live naturally, in our home, and gives us the grace to do it, if we will but accept it. Just how far we have fallen is indicated by the shock with which we apprehend the crucifix:
Christ is the perfectly natural man, but the way He lives is not something that comes naturally to us (anymore). And it never quite will, as long as redemption is not complete. The best we can do is imitate him, ask for His grace, and hope we can through Him learn to live again in a truly natural manner. In the meantime, we can console ourselves with the knowledge that the strangeness we feel, the feeling of never quite fitting in or knowing quite what to do, is a consequence of the Fall, and will be with us to some degree for the rest of this life - but it is not the end of the story, and we can look forward to truly being home when history is finished.
And we can even in this life get a taste of what paradise - another word for living in our true home - is like. We know that in paradise we will live in the presence of God and no longer feel the longing that we do in this life, that something isn't there that should be but we can't quite say what. God will fill us and we will rest satisfied in Him. It's difficult for us to imagine how this would be possible, how we could rest in God without becoming bored (another indication of our fallen nature). For me, I imagine paradise as a "dynamic restfulness", active yet not going anywhere or feeling the need to go anywhere. One way I get an idea for this is playing Irish music; when you get the rhythm right in a reel, it feels effortless and as though you could ride the rhythm all day without trying but without getting bored. It's that "dynamic restfulness" I strive for in my playing and when I approach it, I feel I am getting a little taste of heaven. This is the Irish reel Lucky In Love: