"A good conscience is a continual Christmas." (Benjamin Franklin)
How does one keep a good or 'clear' conscience? Quite simply: "By this we shall know that we are of the truth and reassure our heart before him; for whenever our heart condemns us, God is greater than our heart, and he knows everything. Beloved, if our heart does not condemn us, we have confidence before God; and whatever we ask we receive from him, because we keep his commandments and do what pleases him. And this is his commandment, that we believe in the name of his Son Jesus Christ and love one another, just as he has commanded us. Whoever keeps his commandments abides in God, and God in him. And by this we know that he abides in us, by the Spirit whom he has given us." (I John 3:19-24) When scripture speaks of the heart 'condemning us', it is speaking of the action of the conscience. Abiding in Christ Jesus is the very best way to keep a clear conscience. So, perhaps the better question to ask is how it is we learn to 'abide' in Christ Jesus?
Abiding means more than having a casual relationship with Christ - that is religion. Going to church once a week, saying a prayer before meals, and owning a Bible doesn't make for a relationship - it makes for the 'appearance' of being a Christian. To discover what the Bible teaches, then putting those things into action, adjusting our behavior when prompted to do so by the Spirit within - these are signs that we are learning to 'abide' in Christ.
Abiding also involves not wandering in the waiting. Abiding means we are sustained IN the waiting. I cannot tell you how much difficulty I have in waiting for something to happen when everything inside of me wants to just see some 'action' occurring. When we learn to abide in Christ Jesus, we are also learning to abide inside his timing and his methods. We don't choose the moment he will act - he does. We don't choose the way he will move - he does. We learn to trust both the timing and the methodology he will use to accomplish his purposes. How on earth do we do that?
The most important part of 'abiding in' Christ is to just learn to 'settle into' him. We don't buy a house, get the title in hand, and then walk away from it. We move into it, get 'settled into' it, and we abide there. We need to 'move into' Christ - by taking time to get to know his Word (the Bible), listening to his voice (through song, good teaching, things that catch our attention in scripture), and talking with him (not through 'canned prayers', but with an open heart that shares hurts, hang-ups, and happy things). The more we 'move into' Christ, the more we will sense he 'abides' within. Just sayin!