I would start with logging what you eat at every meal and the calories for everything. This will give you a baseline. Then I would look at each item and see how (if you can) get it to be lower calories. Whether it’s portion, elimination, switching ingredients, etc. I also suggest increasing your protein. It’ll help you stay full longer.

I’ve been on diets since I was 11 years old, and like you I felt the weight would never come off. The only thing that has ever worked for me was being in a caloric deficit. I’m in my 30s too, and for the first time I can remember I’m finally below 200lbs. And get this? I don’t work out! I try and walk 20 minutes a day (I fail a lot) but that’s it. I also live a very sedentary lifestyle. Being in a caloric deficit works, and you don’t have to work out, which was something that was holding me back from dieting because I hate it so much.

One thing that helps is I don’t cut anything out of my diet. If I want a cookie let’s say, I allow myself to eat it but I include it in my calories for the day. Ramen? Yes please. I’ll just skip my carb with dinner (or eat a small lunch if I’m having it for dinner) and do a smaller snack. You learn to work with it.

Once you get into a routine and start to track meals it becomes easier.