Trying to change all your bad habbits at once is never going to work! That's a big reason that diets don't work well (but that's a blog for another time.). If you try and cut out all the pop, the sugar, the salt, the carbs and the alcohol all at the same time, there is NO way you succeed, and if you do, you are probably not staying sane very well. So my advice is always pick ONE bad habbit at a time, start with a managable one right out of the gate. Make your first change one that you know you can do. It will help encourage you along the way and it will give you clues as to how you can be successful in other, more difficult changes.
Here is a sample from a change I made:
I NEVER used to eat breakfast and if I did it was something awful like a pop-tart. When I kept hearing all the postive benefits of making sure you ate first thing, I decided that with all the sports and activities I was doing, I should give it a shot. Well, it turns out there are not a lot of breakfast foods I actually like. I discovered however, that frosted flakes without milk were my thing. So that's where I started. I was at least eating something. Then I had a friend who introduced me to Special K (in milk) one day. I loved it! So that was my next go to. Finally, I was in the store one day and decided to get something new. I reached for the next healthy cereal. I am now eating Kashii Go Lean Crunch every morning in a bowl of skim milk.
It took a little while but each step was a little better than the next, and now I cannot survive a day without it. It is now a habbit. That's what you need to work toward- habbits, good habbits.
So maybe your biggest daily diet issue is the number of pops you drink in a day, start there. Let's say you drink 10 in a day. Replace one pop a day with a water (flavored if it helps, because it's still going to be better than those pops!). Once drinking only 9 pops a day is a habbit, analyze the first step. How hard was it to replace only 1? What time of day was the most successful for the replacement? Was plain water better or flavored? Are you missing that 10th pop?
Take those anwsers into step two. See if you can easily try to replace two pops this time. If it was easier first thing in the morning, stick to that. If flavored water helped, keep that going. If you miss #10, think about why and see how you can tackle that. Keep going until you have maybe one pop a month! WHOA, can you imagine. Don't worry, everything in moderation. You don't have to loose the pop forever, just not 10 a day!
That's not to say that you cannot try to tackle more than one bad habbit at a time, but only if you think you can handle it. If you struggle to swap the pop, it's going to be even harder if you are trying to change something else as well. Keep to a managable amount of change and don't worry about going cold turkey (it won't work for long anyway)!