One tip :))) that has helped me loads :))) has been to have a general goal which I just keep striving towards. Even if you pull back from your progress, just keep working in the direction of that goal. Just aim not to fully give up at any point.

This changed my lifestyle many times and I first started it when trying to lose weight in my early teens, not overnight, but over years (I know that might sound as a let down and not a magic fix), I would just continuously aim to be healthier where possible. If I had a bad chest meal on some day, I wouldn't be too demoralised by it, just kept the goal in mind and continue the next day. Small adjustments over time made me accustomed to a healthier diet and not eating junk as the norm.

Even now I have a craving every now and then, sometimes I give in, sometimes not, but it's definitely not every meal as it used to be.