I was addicted to coke or pepsi before but somehow I managed to get over with it.
How did I do it? From every meal and snack coke session I made it one-two glass a day then three to four times a week then twice a month then once a month. Now, once in a while...like once in two months, really very rarely these days. I got over with it totally for at least 6 months.
Now, I'm contented with fresh fruit juices like lemon, banana, mango, pineapple...anything that is in season.
Addiction is also a mind-game so the more you don't think about you wanting to drink coke the less you crave for it. Indulge in activities that make you thirst a lot then quench it with water, lots of water. You'll get by.
Just do it slowly! Nobody is over with any addiction in one go. It takes time! You have to be disciplined too!