You would do it in incremental steps, depending on where you are at in your journey. Let's take the worst case. Say you are addicted to porn. The first step is to stop looking at the porn and remove all of the porn that you have. That is the first battle. After that, which is difficult on its own accord, you have a couple of options. I find that people who have major problems in this area have sex at too high of a place in their life, i.e. it is on their mind all the time. So in that case, the next step would be to remove sex from that place and spend your time doing/focused on other things. That in itself can help a lot in stopping the lust because the mind is not focused as much. And then, you keep addressing whatever problems come up after you have done all of that. I mean, like I have said before there are levels, as in, you know, it is better to lust with your thoughts than have a massive porn collection. The key is, is to recognize this as sin and take these incremental type steps to deal with it. Can we as people stop every impure thought? doubtful. But these steps go a long way towards doing it.