If you are anything like I once was, you may have a terrible (health wise) and expensive soda habit. I tried for years to break it and failed miserably each time. Then about 5 years ago, I came up with a method that worked, and eventually cut my $1000 a year soda habit down to $0.
My main problem was that when I tried to quit drinking soda, I always felt deprived. The deprivation had me always thinking about it and at some point I would cave in and start drinking soda again. I had to come up with a way so I didn't feel deprived.
My simple solution was to say I could drink as much soda as I wanted, but I had to drink a full glass of water before I could. The result was that I didn't feel deprived of my soda since I could have as many as I wanted, but drinking a full glass of water before each one made it so I didn't drink nearly as many each day.
After a month, I made the rule that I had to drink 2 glasses of water before drinking a soda, and that eventually increased to 4 glasses of water over time until I was in the habit of drinking water instead of soda. I'm not sure it that will work for you, but it is certainly a set of baby steps that are worth a try if you are looking for a way to break this type of habit.