Something that can help is "greasing the path" to the task so you make it easier to start. Say you want to go to the gym tomorrow. Instead of thinking "I'll see tomorrow when I can go", you can block time in your calendar, get your gym bag ready by the door, text a friend to go together at an agreed time, etc.
Some of the tools I create for work are about fighting my own procrastination, half of the rest are about fighting the procrastination of others.
If your partner won't go to the gym, you can't make them, but you can make sure their gym clothes got washed. If your coworker won't do things, you can't make them, but their boss can, and that's easier if you've made the task more straightforward.
