User Forty2 made a great comment and I agree with so much of that.

Do not focus on stopping a behavior. Focus on slowly moving into a new behavior until the old one slowly disappears.

You can use transitional steps. What I did, was to change from regular soda to diet, and I did it by slowly mixing diet into the sugar until the proportions had reversed. And eventually you got to the point where it was mostly diet. There, I successfully changed to diet soda, I didn't do it overnight, I took a month to do it and it was easy that way.

This applies in all areas of your sugar consumption.

For example, if you're taking two measured tablespoons of sugar in each coffee... Start by reducing that amount by 7%. Yes, literally that small amount... But you layer one change on top of the next, on top of the next, once you have some success. It will take you literally 3 days to get used to the smaller amount of sugar, and you'll barely notice it... And once that feels good, you reduce my another 7%