The internal and external obliques, which I like to call "nature's girdle," are located at the sides of the rectus abdominis. They are the muscles you use when you bend sideways at the spine or twist at the waist. They also contract to compress the abdomen, so you should work them just as hard as you work the rectus abdominis. Adding a twist to crunches works, as well as dumbbell side bends, but be careful not to use any jerky motions, especially if you've had back problems.
How to do a Turkish get-up: Holding one kettlebell by the handle with both hands, lie on your side in a fetal position. Roll onto your back and press the kettlebell up toward the ceiling with both hands until the weight is stable on one loaded side. Release your free arm and free leg to a 45-degree angle with your palm facing down. Slide the heel of the loaded side closer to your butt to firmly grip the floor.
Cut back on calories. The most important part of losing weight is not working out until you collapse — it's your diet. If you burn 500 to 750 more calories than what you eat every day, you will lose 1–2 pounds every week (any more than that is considered unsafe weight loss). There are tons of little changes you can make to cut calories from your diet, from replacing high-calorie dressings with vinaigrette and asking for all dressings/sauces served on the side, eating at the table instead of in front of the tv, skipping cheese and other fatty additions to your salads and meals, using smaller plates, leave off the whipped cream on your coffee drink, and on and on.