take small steps.
1. Stop drinking soft drinks (soda/pop, most juices, lemonade, most pre-made teas, etc)
probably the biggest one for a lot of people is this. It's ridiculous how much sugar and calories you get from shitty drinks that do nothing for you. I try to stick to drinking just water, black coffee, or tea with no/little sugar added.
^that will also likely be the hardest habit to break. I don't know how many times I've had to kick that habit.
2. Have a salad with lunch and dinner, + try to avoid using a lot of dressings.
pretty easy to do if you like having salads, I love spinach and would suggest it for your salads.
3. Make your own meals from scratch. You'll cut out a lot of sodium, sugar, and fat doing this plus you'll likely enjoy this food more.
bit harder especially if you feel like you don't have enough time, I suggest making a 1 or 2 week meal plan and then repeating it. It'll make it a lot easier for you.
Try to do just 1 of those to begin with (for a month or 2) and then add 1 of the other ones and go forward from there. Also don't beat yourself up for not sticking to a healthier diet it doesn't help you to do so.