You cannot work on a specific body part. You have to work on overall fat loss and toning.
Try to eat small but frequent meals. Avoid long gaps in between meals. Drink a glass of lime water in the mornings to lush out your system & avoid bloating.
Avoid junk as far as possible.
Exercise at least 4 times a week. Include exercises that tone your back and abdominal muscles too.
Lastly be committed. Remember it's a lifestyle change and not a one time thing. It's a balanced intake that will last you longer.
All the so called diets and singular ab exercises or ab machines will not give you targeted results. The fats will remain as it is. It's all about overall work out and balanced diet