If you want you and your kids to practice more self control here are the 3 things you need:
1. Keep your goal in mind
2. Think of future you
3. Ability to distract
These are the 3 features of executive function (mental skills that help you get things done) needed to cultivate and practice self control.
Keep your goal in mind. You know what you are working towards. That future goal and reward is worth the short term consequence now.
Think of future you: You are able to take your tempting goals of now - that Halloween candy is going to taste delicious and shift it toward the future goals - future me is healthy. Ability to think of future you.
Ability to distract: The Halloween candy may be sitting right in front of you, but you decide to have some water instead.
For today do a Marshmallow or Treat test with your kids! Put their favorite treat in front of them at a table and tell them you will be back in specified amount of time. If they wait for you to get back, they get 2 treats and if they don't then they get the 1.
Ask them why or why not they were able to wait. You can even set up a camera. Kids tend to be very good at the distraction part!