Its something you decide deep within you. Its like a contract signed between your mind and body. Its a pretty drastic change of mentality, a change that when is made, you give your 100%. There are no doubts. You are committed. Whatever it takes. Its not something you think one morning and few hours later you totally forgot... Its a big personal decision. You can't be delusional to yourself, you can't do it to your self-esteem, or you'll never believe you can achieve what you truly want. The switch from somewhat lean to shredded, this is what I'm talking about. You can spend months thinking about getting in that perfect shape you want, but still the pleasure of food, relax and not being on a tight schedule override that first desire. Soon or later though, you reach a point where you are sick of dreaming...life is not a dream! You WANT IT. So you start ACTING on the realization of that dream. I can't tell you what's the trick to make that mental switch happen. i think varies from person to person. Certainly its not an over night thought, but an idea that took form in your mind with time.
The most relevant aspect about this switch is food. Food must become a MEAN to get what you want, no longer a TREAT (even if healthy, those 3spoons of peanut butter weren't really needed...) What your body doesn't need, I consider a TREAT. An extra. Your body doesn't need so much as you think, when we are talking getting real LEAN (below 10% or so). Actually your body fights and hold on that fat, because "he" (I consider body a person lol) doesn't like to expose muscles and veins, he's like a shy type you know, feel comfy covered with some fat. But you, your MIND, think quite the opposite. So I'd say the switch from being lean to fuckin shredded is all a MIND game, where food approach is first thing that gotta CHANGE. You gotta love shredded abs more then whatever you eating and holding on now. The moment you do it, even after one DAY, u feel empowered. Go on a week, you are ON IT. Motivation will build up, as your muscles start to show. I think the first 2-3 weeks are the toughest. Body senses the changes (not necessarily training wise, but FOOD wise) and you'll feel very weak, depending on how much cals you been cutting out. But that's a GOOD sign. The switch is working. You are on your way to "phase 1", as I call it. The phase were all you can say when you look at the mirror is...yeah, I'm shredded as f**k!
Get your switch mode ON ;)