"Eat smaller portions" is lousy advice. Smaller than what? A lot of people, especially women, already eat too little and eating even less won't help at all. The solution might actually be eating more.
Start logging your food intake with e.g. Myfitnesspal if you're not doing it already. Calculate your optimal calorie goal (see the post Want to lose or gain weight by Scotty K) and find a macronutrient ratio that works for you. Mix it up and try a few different approaches for the first weeks to see what works for you. Make sure you eat enough and don't starve yourself.
As Matthias points out, belly fat is unfortunately often the most stubborn. Keep going and don't give up!
Hi I really want to lose weight 10kg is my goal..but as you said my major problem area is my waist..I have started crunches but..I want to know what other excecises to do to lose weight
You have to control what your putting in your body. I've been meal prepping and working out consistently and it is slowly coming off. I eat 5 smaller meals a day and have actually lost weight. Portion control is everything and you have to make yourself eat. Watch your sugar intake cut out breads and stick getting your carbs from meats like chicken and lean ground beef and rice such as jasmine. I hope this helps !! Good luck :)