Does skipping one meal a day help lose weight and make your stomach flatter?

no. You can lose 10 lbs/mo with this plan: Stick to fresh fruits and veggies, salads, eggs, chicken, turkey, fish, whole grain cereals and drink lots of water. Avoid fast foods, junk foods, greasy foods, sodas, coffee or starches. Noodles, rice, potatoes, bread, muffins, bagels and all forms of pasta turn into sugar in your body. Eat only what fits in a soup bowl.

no second helpings. Never eat out; restaurant food has too much fat, salt and preservatives. And of course do some exercising.

No. Skipping the meal triggers the body to store more fat because there is no longer a regularly source of food. You would be much better off lowering your caloric intake and spreading this out across the day with smaller meals eaten more frequently. Don't eat less than 1200 calories for female and 1500 for male or you risk sending you body into panic mode again. You have plenty of time that if you drank enough water (2000mL), cut out added sugars (fruit is fine), and exercised daily (30min walking is enough), you would end up losing weight.