The Card with Two Sections
Your daily index card should have two sections.
One section contains the actions you will take on positive matters. Some will be urgent and some less so and yet they deserve routine attention; e.g. study Spanish.
The other section is a list of the actions you should not take. [Snacking will be a common one for many of us.]
Every time you take an action that relates to any item on your list, make a mark next to the item.
The more time you spend on the positive items, the less time you'll spend on the negative ones. Let the good drive out the bad.