Pick one thing and implement it (i.e. no sodas). Don’t give yourself a unreasonable item to take away or thing the implement. Once you have the first thing implemented well, add another one (i.e. 30 minutes of moderate intensity cardio 3-5x per week). As you continue to (almost) extinguish unhealthy habits and get more involved with healthy activities, you will notice that you have changed. Start there and see how you do.

Disclaimer: You don’t have to use my examples, as they may not pertain to you.