First and foremost love your body and if you want to see changes make them out of love for yourself not hate! Health is important but I believe all bodies are beautiful. Self love always needs more promoting especially in this day and age
Diet is the most important thing for a toned stomach. Cutting extra sugar and carbs will help. Drink lots of water and cut out sodas. Eating foods high in protein will help keep you from overeating and so will the water. A glass of water before each meal is recommended for that purpose.
I’m big on weight training but cardio will really help the waist area although it doesn’t have to be for super long periods of time. 20-30 minutes a few times a week may be enough as long as one is eating clean.
A strong core is important but doing ab exercises will not be enough. The other things I talked about are so important.
Also: no one looks the same when they wake up as they do when they go to bed; bloating happens! Just nature, don’t be discouraged :)