Habit formation isn't wishful thinking, but I'd say that habit design is.

Habit formation itself comes from routine. Not the desired routine. This is why we have bad habits.

Good habits are hard, because they are not what we naturally tend towards doing (or we wouldn't try to build them, we'd already have them). Habits are self-reinforcing, and are really based off ideas of success and failure. If we fail to (and regret our failure to) carry out our habit, that is discouraging and actually makes it harder to keep up with the habit.

The best way I have found to develop wanted habits is to never recognize failure in the habit. Always recognize success. You want to do something habitually, keep track of when you do it. Don't keep track in a way that lets you notice when you fail to do it. If you want to do something daily, don't mark on the calendar when you've done it, don't write the date that you did it the last time. Instead write down a simple tick each time you've done it. Increment a counter. Watch it go up.

Say you want to start to wash your brontosaurus (named Rex) on a regular basis, say you never wash him currently. Start by washing Rex and mark a tick down. Then the next time you think about it, wash Rex, and mark a tick down. If you want to do it daily, the next time you think about it, consider whether you already washed him today. If you haven't, wash him, and put down a tick.

Don't tally the ticks up. Don't look back to see how frequently you actually washed him every day. Don't get frustrated because for the past three weeks you washed him daily but last week you missed him three times in a row. When you worry about how well you are washing him, just think "Did I wash him today?" and then wash him if you didn't.

You'll start washing him every day. Or you'll start to wash him every other day and be happy with it. Or you'll wash him from time to time. Think about the results instead. Do you have a brontosaurus that is sufficiently clean? If you do that's great, keep it up, whether you do it daily or monthly. Do you not? Then consider what else you could do besides cleaning him yourself to make him cleaner.

Whatever you do, don't just get mad at yourself for not doing it and demand from yourself that you do it more often, and then promise yourself that you will. That won't work. You'll maybe do it for a bit and then burn out from frustration and failure.

You can always do something like set a reminder if you don't think about it. But if you remember and avoid it, and then get angry with yourself for avoiding it (or rationalize your avoidance), you're doing the opposite of what is needed to make a habit.

If you find you are avoiding it (Ah man, I'm too tired right now.) don't tell yourself you will make it up tomorrow. Don't get angry with yourself. Don't even acknowledge it. It's a habit, not a chore. It's something you want to do more frequently, not something you have to do. Acknowledge when you do complete it, not when you don't. As soon as you start to argue with yourself ("I should do this, but I don't want to") you're already losing the battle. Don't consider at that point what you should do. Just do it, or don't do it. Notice and feel good when you do it.