With soda, you're dealing with two things:
1. the sugar
2. the caffeine
I find sugar tends to be somewhat self-reinforcing, and so just cutting down on that in general helps deal with that side of things.
Then there's the caffeine. For that, I recommend switching to teas or coffee. I mostly drank soda for the caffeine up until university, at which point I was drinking about 1.5L a day. At that point, it was obviously silly (especially when I went to the dentist and they immediately noticed I drank a lot of soda just by looking at my teeth). So I gave up soda for coffee.
Only problem was, I really disliked the taste of coffee; so to get it over with more quickly, I simply started drinking plain espresso shots. 2/3 of an espresso shot is about the equivalent of the caffeine in a 12 oz can of soda.
Espresso shots also have quite a powerful taste to them; one which varies quite a bit depending on what sort of coffee shop you go to. Some of this taste will stay in your mouth for hours (or until you next eat), which is beneficial both because coffee is an appetite suppressant (and so you won't even really want soda or other sugary snacks) and because it enhances the psychological (placebo) effects contributing to your caffeine buzz.
This will likely strengthen your dependence on caffeine; however, plain espresso shots have effectively no calories or other negative stuff associated with them, and some amount of coffee intake can actually be good for you. So if you really want to get off caffeine at some point in the future, fine; but if not, no worries, since it isn't really harming you any more outside of the dependence itself.
Of course, the major caveat to this is it has to be plain coffee or espresso. Starbucks dessert coffee drinks actually have more sugar and such than even sodas. Avoid creamers, milk, and so on, as they only make it simultaneously less healthy and more expensive. Depending on your past experience with coffee, this may be somewhat repulsive at first, but be gung-ho about it long enough and you will start to enjoy it.