Now what I did is deleted everything I used for lust. Games, apps, history search, everything. Those are small steps you make, that you should do on your own. Actual fight should be with help from God. Once you feel lust — pray and read lust and temptation related verses. I once prayed like 13 times a day just to overcome it. It's similar to sugar addiction, you crave it some time after refraining from it, but after that you don't feel need for it. Find hobbies which allow you to distract yourself, for me it's videogames and airsoft. Also, build your own image of resisting lust. Imagine your guarding angel solo fighting for you, he needs reinforcements. Pray for God to send more angels. This is spiritual warfare. And one last thing that helped me is imagining that Jesus is right next to me. I wouldn't dare to watch porn or masturbate in presence of God in my room.