Yep, nothing more than common sense. You know instinctively what's good and bad for you, and cutting out coke will make a huge difference on it's own. Keep using fresh ingredients. You're probably already finding it's quick and easy to cook from fresh, still tasty and so much healthier.
Your cravings for junk food and fizzy drinks will pass quicker than you think, but in the meantime, since you seem to be trying to cut it all out at once, don't worry about the occasional slip. Choose one thing to really focus on and make sure you don't slip on that, but don't beat yourself up if the other things slip now and again. But if you manage it all at once, even better.