Commitments made to other people mostly get kept. Someone is expecting you, and the cost of not showing up is a face you have to look at.
Commitments made to yourself are a different problem. There is no meeting, no one waiting, and the only person who will ever know is the one who is currently very tired and has a good reason. Most people are not weak-willed. They are negotiating with themselves at the worst possible moment, alone, with no record of what was agreed.
Here is a method that works on that specific problem.
Make it small enough to be boring
The most common mistake is scale. "Get in shape" and "fix my sleep" are not commitments, they are directions. There is no Friday on which either one is answerable, so they never produce a yes or a no, only a vague sense of falling short.
The test is whether a stranger could look at the commitment on Friday and say, with no interpretation, whether it happened.
- Not "exercise more." Walk on Tuesday and Thursday.
- Not "be better with money." Move twenty dollars on payday before anything else.
- Not "fix things with my mom." Call her once this week.
Small enough that keeping it is unremarkable. That is the point. You are not trying to transform anything this week. You are trying to build one instance of evidence that your word means something.
Say it out loud to one person
This is the step people skip, and it is the one that does most of the work.
A commitment that exists only in your head can be edited silently. A commitment you said out loud to a specific person has a witness, and the witness does not have to do anything except remember to ask.
Choose someone who will actually ask, and who will not turn a missed week into a character assessment. That second condition matters as much as the first. If the cost of admitting you did not do it is a lecture, you will stop admitting it, and then you will stop saying commitments out loud at all.
Set the day you will answer for it
Pick a fixed day. Same day every week.
The specific day is irrelevant. What matters is that it does not move, because a deadline you can slide is not a deadline, and because the fixed day is what starts showing up in your head at the moment of choice. On Wednesday night you are not thinking about your goals in the abstract. You are thinking about Friday, and about saying out loud that you did not.
That small piece of forward pressure is more useful than any amount of motivation.
Answer honestly, especially when the answer is no
The whole method collapses the first time you fudge it.
"I mostly did" and "it was a weird week" are not answers. Kept or not kept. Say which. Then, in one sentence, say what actually got in the way, without apologising for four minutes and without building a case.
Missed weeks are not failures of the system. They are the data. A person who has missed the same commitment three weeks running has learned something specific and useful: that this commitment, at this size, in this week, does not survive contact with their actual life. That is a signal to change the commitment, not to change your opinion of yourself.
Keep the record
Write it down. Two columns, the commitment and whether it held.
After a month it is a scrap of paper. After six it is the only real evidence anyone has about what your word is worth, and it belongs to you rather than to a file someone else keeps.
That record is also the thing that gets you through the weeks when nothing feels like it is working. Motivation is not available on demand. A page showing eleven of the last fifteen weeks kept is available any time you want to look at it.
Start this week
One commitment. Small, specific, said out loud to one person, answered for on a fixed day.
Not a system. Not a new version of yourself. One thing you said you would do, and then did.