Plan your meals (and snacks if needed) - have a time each week you shop and prep. Shop online if possible.
Eat something every 3-4 hours (I know fasting is fashionable, but I find life easier to navigate - ie I am less likely to faceplant in a cheesecake - if I don’t get over hungry - a bit hungry is fine)
Eat protein and fibre with every meal.
Get enough sleep. Lots of people eat loads more when tired.
If you aren’t loosing weight, check your calorie deficit and adjust - you probably will do fine by eating healthily though.
Make things as easy for yourself as you can. If you don’t like cooking and can afford pre-prepped veg then get them. Have some ready meals (made by you or a shop) in the freezer, and an option get food down you instantly if you are ravenous or v tired. Eg eggs on toast.
Don’t have temptation in your line of sight - put cereal in the cupboard, office biscuits in a tin.
Build up your steps and - slowly - an exercise habit. Exercise doesn’t do much to help you loose weight, but there’s plenty of evidence it helps you keep it off.
Don’t be too strict - it often feels easier to totally ban things than have some treats but the reality is you will almost certainly fall off the wagon.
If you have an emotional relationship with food, work on that via books or therapy if needed.