So before you even begin dieting i suggest you take a week of eating normally and track what you eat in a week.
Make sure you really measure your portions so you get an accurate idea of the calories you are intaking.
Usually that is eye opening enough for a lot of people if you base it off of an average 2500 calorie diet.
There's a lot of diet routes you can go , but what I've been doing lately as a diet and food tracking strategy is I've been tracking my liquid intake as well as my food intake with an intermittent fasting diet app. Theres several you can use but I currently use "Simple." The official app is on Simple.life This just allowed me to cut down on the meals I was eating per day and so far it's gotten me down 30 lbs and thats not including the fat I've probably replaced with muscle. There are many different dieting routes out there, but the two main take-aways are calorie deficit no matter what strategy you use, and make sure whatever diet you do you are doing it safely.
The thing you do have to remember no matter what diet route you take is that it is a slow process, and the only way you're gonna do it is if you stay consistent. Working out will only get you so far, but the diet is 80% of the weight loss.