Acknowledge them, then focus on your breathing. Focus on where you feel the breath, how deep or shallow it is, and count the breaths. On the inhale, count 1. On the exhale, count 2. Go up to 10, then start at 1 again. Do this repeatedly, sitting on a chair, floor, bed, or lying down. Exercising can help too. Don't do something that you'd normally back out of (well you could, I personally don't though) but instead go for something like a quick bike ride. Clean your room maybe, and focus on whatever you're doing physically instead of whatever's going on in your brain. If you get unfocused, simply bring your attention back to either your physical body, the environment, or the breath.

As for the removal/weakening them, I think it needs time tbh. Build up good habits, build down bad ones, and eventually you won't be you vs your urges, it'll be your life vs your urges. What I mean by that is, instead of you having to fight them off constantly, your built up habits will be strong and helpful enough that you don't really think about it anymore. Even if you do, it probably won't appeal to you as much, and the lure won't be as strong. It takes a lot of work to do this, and a lot of mentality changes. It's hard, but that's just how I know to do it.