Most of our habits are acted out subconsciously, without us even realizing what we are doing. The reason why? We evolved to be able to put repetitive things on a mental back burner to free up our minds to concentrate on other tasks at hand. It would really be a drag to have to concentrate hard every time we did something like walking. This is how bad habits can creep into our lives without us realizing just how much of a hold they have on us until it is too late, and we begin to see effects that we don't like. Extra weight that seems to have crept up out of nowhere, ill-fitting clothes, bad eating habits to name a few.
The awesome thing about good habits is that one you initiate them, they are just as automatic as bad ones. If you have things in your life that you aren't liking, something needs to change. The difference between who you are and who you want to be is what you do. Figure out what habits are producing the undesired effects, think about what little steps you can do to change them, then hold yourself accountable to follow through.
We all have routines called "keystone habits"...behaviors that unintentionally result in a cascade of actions that carry over into other aspects of our lives. Exercise is a common one, because it conditions you to put effort into something productive that you can see visible results from on a regular basis. Once most people start regularly exercising they subconsciously adapt other healthier and disciplined behaviors as well. It's one of the awesome mental benefits of working out. Find out what your keystone habits are, it's a game changer. Once you know what really makes an impact on you it is easier to motivate yourself to stop what you want to stop doing, and start what do wish to.
One of the ways I got out of the habit of eating unhealthy things was to think more carefully about what I'm putting into my body. As the old cliché goes, we literally are what we eat. What you're eating is going to be broken down to build your body. I started looking at junk food as what it really is, something that I probably didn't want chilling in my body, dragging down my energy. After a couple weeks of mindfully concentrating on this, junk food lost much of it's appeal. The first couple weeks of cutting out sugar sucked, but once they were over the cravings stopped. After that it was smooth sailing.
You can make things easier on yourself by first realizing you have habits that are producing results you don't like (that in itself is major) and then being more mindful when you catch yourself doing them. Consistency is important, once you repeat something 21 times it becomes a habit, it comes naturally. The key is making it that first few steps, and keeping at it...little changes add up to an epic lifestyle, but no one is coming to do it for you. The choice, as always, is yours.