Turn the wish into a Tuesday
Pick one wish. Not the list. One. The people in Norcross's study who succeeded had a specific thing, and the whole argument of this book is that a Tuesday can hold one sentence, not five. If choosing between wishes is itself where you get stuck, there's an earlier book in this series about that, Pick one, and its advice holds here.
Now write the Tuesday sentence. It has four parts and it fits on one line. What you'll do, in the smallest form you'd still count. When, as a day and a time. Where. And what you'll do when the ordinary thing gets in the way. So not "get fit" but "on Tuesday and Saturday at ten to eight I'll go out of the front door and run for fifteen minutes, and if I get home after seven on Tuesday I'll walk for ten instead". Not "write the novel" but "on Monday, Wednesday and Friday at half past six I'll write for twenty minutes at the kitchen table before anyone else is up, and if I sleep through I'll do it at lunch on my phone". This is the form Milne's exercise group used and the form that Peter Gollwitzer and Paschal Sheeran's 2006 review of 94 tests found to have a medium to large effect on whether people did what they intended. It works, the review's authors suggest, because it hands the decision to the situation. When ten to eight on Tuesday arrives, the decision has been made already, on a Sunday, by someone who wasn't tired.
The least version is the part people resist, so I'll say it again. The size in the sentence is the size that survives the worst ordinary Tuesday you can imagine. Not the best one. If the sentence is one you'd only do on a good day, the good fortnight will do it and February won't. Fifteen minutes is a run. Two hundred words is writing. One page of the bank statement is sorting the money. You can always do more when a day is generous, and the Sunday five minutes will let you raise the size when three weeks of Tuesdays say it's safe.
And write down the wish too, somewhere else. Large, as large as you like. It's the picture and you're allowed the picture. It just isn't the sentence, and the sentence is the only thing that's going to be at the door on Tuesday.
If you're reading this on the first of January, good, there's a push behind you. If you're reading it on a Wednesday in June, better, because chapter 11 said the ordinary day is the honest place to start. Write the sentence today. Do the least version tomorrow.