AC 12407811, there is no simple answer to how you do it. It is a very personal quest.

You need to strengthen your body and mind as a whole, and then, equally important, your spirit. To strengthen your spirit, you need to train your willpower. And to train your will power you will need a lot of physical and mental training as a support. It is an evolutionary cyclical process involving three interconnected factors: body, mind and spirit.

For me it was a mostly process of obtaining self-knowledge and knowledge over human sexual energetics and other metaphysical subjects. I also did running, bodybuilding and martial arts for 3 years. The physical training helped to increase my awareness over the flow of physical energy (the energy flowing inside my body) and I learned to control it better with my mind. Hence I've become more resilient to sexual arousal. I also did prolonged fasting..and some meditation, which helped me with the mental factor. Meditation is important to ease and calm the mind from destructive impulses such as rage and lust. I've also cultivated theoretical principles to convince myself to not give in to desire. You need to develop your own personal theory of why you "should not", and trust me: it must be a flawless one or you will eventually run into doubt. You need principles that will stick with you in the hardest situations.

More info:
Thread: Your Brain on Porn (Page 10)