First off you realize its an addiction, so then you must realize, like smoking, your not going to quit on the first try. It will be many tries before you stop for good. Try not to give in as long as possible, then once you give in, try to extend the period again. Things that can help is watch the tv and use the computer in a public area, like the living room or any other room that your family can easily come and go whenever they please. Right when you get the urge, go do something... go to the kitchen and eat some yogurt, a glass of milk, an apple, anything. This will keep your mind distracted. Also, if you hadn't realized, the urge last about 30 minutes. So put those 30 minutes to use, exercise. Exercise for about 20 - 30 minutes, nothing strenuous, just go outside for a walk, a small jog around the block, another thing that keeps your mind distracted. I don't know if your religious or not, but once you've tried everything to stop and you are definitely going to give in, say a prayer for forgiveness right before you masturbate. You might say to yourself, say a prayer before i do this? But God wants everyone to turn away from badness. As long as you realize truly what your doing is wrong, and you never stop trying, he knows your trying to do whats right, that you have it in your heart that you truly do want to stop and are doing your best as humanly possible. Again god realizes we are all imperfect, he also realizes when we try our best to do good, and that is what counts.