The "smallest possible thing" hack is a great one. It also works great for exercise. If your goal for example is to work out every morning before work, instead of setting ambitious goals for what's going to happen tomorrow morning when the alarm rings at 6am, promise yourself the following: "I will physically get out of bed. I will put on my workout clothes. I will do five pushups. If I don't feel like doing anything else after that, I will go back to bed."

When you've gotten up, gotten changed and begun to move, the prospect of going on to do an actual workout becomes like 90% less unpleasant of an idea, compared to how you perceived it from the comfort of your warm soft bed.

It works, try it.