Renunciation depends a lot on Compassionate Understanding. Sometimes when people are asking me this they're having trouble with giving up this or that, I give them a meditation on the dependent arising nature of things. I ask them to trace the object back to where it came from, just try to see some of the suffering that's involved in bringing it to be. For example, someone who's having trouble giving up drugs. I ask, "Can you see that it harms anybody?" They may answer, "No I just do it on my own. It doesn't hurt anybody." So I ask this person to actually trace how the drugs came to be, back to its existence, and how it came to them and what was involved in trying to get it to them. All of the suffering involved in that cycle, and ask them whether they want to be someone who encourages that cycle.
And as far as understanding about substances that confuse the mind, we have to understand how important our awareness is. It's difficult enough to know what to do with the hindrances when we have a clear mind, and to protect ourselves, so when it's clouded by anything, it's even more difficult. So learning how to reflect on how the substance came to be, how the substance came to us, and having compassion for ourselves and others is very helpful to bring about renunciation.
Another thing that helps to bring about renunciation is to develop more confidence, develop more confidence in the Dhamma, develop more confidence inspiring objects, to know actually how to develop more joy in the practice. Because it's difficult to let go of worldly happiness unless we have something to replace it . Suppose you went up to a little 6 year old who liked a tricycle, who loved that tricycle, and you just took it away. What do you think would happen to that kid? Probably start yelling and screaming, "Don't take my tricycle away!" But if you gave them a two-wheel bicycle, it may be a lot easier to give up that tricycle.
So it helps to understand the joy of the path. And if we're having some trouble with too much Dukkha, it may be you're focusing two much on the first two Noble Truths and not enough on the third and the fourth, and understanding the happiness that comes from walking out of Dukkha. Developing more confidence is very helpful for developing renunciation. As I say in the Satipattana Sutta talk, the Buddha said that in order to let go of attachment to pleasant worldly feeling you have to cultivate pleasant spiritual feeling. If we continually hold a negative self-image about ourselves and don't develop confidence, some confidence inspiring objects to give some inspiration, it would be very difficult to give up worldly happiness, because there's nothing to replace it.