I have 0 discipline and hence habit building has always been hard for me. I’ve tried and tested a lot of things on this front. Here is a useful tip that’s helping me out in maintaining my new habits:

One of the worst things people do is hate on themselves after going off track on their routine. This is actually a horrendous habit. And might stop you from starting new things, in the fear that you’ll stop it midway (and blame yourself for it).

My alternate approach is to reaffirm myself that I dislike the thing I want to stop doing / absolutely love what I want to continue doing. Our likes and dislikes are much more flexible than we think.

For eg. I wanted fitness to be a part of my lifestyle. I’ve been working out and honestly it’s hard. I slip. In my diary, I’ve written a page on how good it feels to workout. Every time I slip, I just go read it. Every time I workout, I acknowledge loudly how much I love it.

I’ve also been trying to level down my sugar intake. Every time I slip and add extra spoons of sugar, I tell myself loudly how much this extra sugar sucks in my drink (or whatever you’re having).
Make sure you’re acknowledging it loudly, so that it gets registered in your brain.

The goal is to make sure that you don’t blame yourself, at the same time you let your brain know that this action needs to continue/stop.
Relying on panic to get things done might not be the best thing for your mental health. There’s always an alternative solution!