I have some examples below but my advice comes from a more generalized approach on habits/decision making. What's the point of doing a 30 day super diet if you're miserable the whole time and afterwards you either quickly/gradually fall back into the actions that got you there in the first place.

Make choices and plans when you feel strong/motivated, then set yourself up as best as possible to limit your power/desires to make good decisions when you're less strong/motivated.

Recognize your habits and how you might have "failed" in previous attempts.

Dont buy foods you know youll overeat. Try to only grocery shop when you feel strong/empowered/full.

Try to plan your meal choices ahead of time, and have a backup plan or 2 that might be worse than plan A but better than winging it. Ex: you have to go to work, and there's a fast food spot near that you eat at way too much.

Plan A: bring lunch daily Plan B: have some frozen stuff you can microwave if you forget/don't prepare a lunch Plan C: have a protein bar or some highcalorie snack that'll hold you over Plan D: know of a couple healthier options for takeout, and commit to them before you get hungry.

If you keep failing a plan A, figure out why. You keep running out of time in the morning? Meal prep. You hate the lunch you bring to work? Make something else that might not be as healthy, but it's better still than plans B-D.

It's ok if you mess up. It's okay if you make compromises, but try to make the compromises when you feel strong not in the moment.

You don't need to be perfect to lose weight, you just need to consistently eat less/healthier over time.

Also unless its a nutritious shake/smoothie, dont drink calories. Lmao that's a big one. For a lot of people just getting that number down is enough to make a significant different.

If you have any particularly bad/ingrained habits it's okay to ween yourself off them. You don't need to go from 10 cokes a day to zero, go to 5 first. Or instead of coke, maybe you can switch to coke zero for a month or two first, then switch to flavored water for a couple months then plainwater. Or whatever.