Getting the subconscious to give up it's old habits is VERY difficult (which is why virtually everyone fails or yo'yo's.* And your mind will create whatever the subconscious is focusing on (not the conscious).
It's also why affirmations and other such new age ideas seem great but don't work (most of the time)
Have you ever tried an affirmation like "I am thin & attractive" and said it consciously only in the back of your mind you could hear your subconscious snapping back "No you're not, you're an ugly cow".* If you can't stop your subconscious from being negative, changing is very hard.*

In answer to your question, there's a couple of things I think have to happen
1. You need to accept full & unequivocal responsibility for everything that happens in your life. No if's and's or but's
2. You need to accept the fact the fact that you can't have it both ways.* In other words the only way to change is to accept (at your very core) that you have to start doing things in a different way.* There is a HUGE difference between 'Wishing things were different' and 'Changing the way things are'.* Most of stuck wishing things were different without really doing anything different.
3. You need to find some mechanism to constantly keep the change you want to make (and all the positive aspects of it) in your thought.
*** - Focus on what you really want (at least 10 times per day).* Create a* mental movie of how you would look and feel if you met your goal and play that movie over & over again and really FEEL how you would feel if you were there.
*** - Any other similar way of reinforcing the positive change into your subsconcious (Meditation, Yoga, Tai Chi, Breathing exercises,....etc