Proper diet is hard to define as such for each and every individual. If you are too lazy, you can use this link: http://www.nhlbi.nih.gov/guidelines/obesity/BMI/bmicalc.htm. It will just tell you if you are overweight or not.
I believe its best to have a trainer/instructor to guide you properly if you are loosing your form while doing any exercise or use a mirror. And, have a dietician suggest you what to eat as per your work life balance and the amount of workout you do.
When I had begun gym training, I used Kris Gethin's book as my guide [The Bodybuilding.com: Guide to Your Best Body] and here n there took help from the trainers, which is quite good since it also suggests variations of diet plans.
Since i have also started working out in gym since few months and have lost few kgs so here is my opinion. You have not mentioned properly about workout.In order to burn fat you need to have more muscle, the amount of muscle you have is directly proportional to calories you burn. Add weight training to your routine and food which has good amount of lean protein(egg whites, paneer, chicken breast, fish etc) which help in muscle building.
You should always focus on building muscle to loose weight. Have a mix of weight training and cardio.Crunches will help you grow abdominal muscle but will not reduce your belly fat if you have beleived so.You should include more of compound exercises like deadlift,squats etc... to burn more fat.Avoid completely junk food and reduce the sugar intake.You can ask for more questions if you have any particular doubts