I have 12 weeks

Sounds like a good goal for 12 weeks. It's best to lose weight slowly so that it will stay off. I suggest keeping a food diary and write in it every day. Write down everything that you eat, even the little bites that you take while making dinner or whenever. Replace all high calorie drinks including fruit juices with water and skim milk. You shouldn't waste your calories on drinks that don't fill you up, instead eat lots of fruits and vegetables. Make sure that your diet is balanced and that you are eating things from each of the food groups every day: Proteins, Starches, Fruits, Vegetables, Fats,and Dairy. Water retention is caused by too much sodium in your diet so you should avoid salt when possible and drink plenty of water to prevent bloating. Find some fun workouts to try out from online magazines like shape.com. There are tons of fun ways to tone up like yoga, pilates, jogging, interval training,weight training. Try out a bunch of different workouts to keep you from getting bored.

it's impossible to loss 12lbs. is short period of time, except if you have great metabolism, based on my experience in my more a year in weight lifting and fitness, you can loss a weight and have a descent physique if you have strong discipline and determination/motivation, follow the simple of "burn more calorie that your body can replace", do cardio-exercise for 45-60 min. and follow a good sensible diet, eat small amount of food every three hours, avoid simple carbs, unhealthy fats, sweets and etc...you can also use green tea upon waking up in the morning and followed by your cardio-exercise with empty stomach...hope this help!

12 pounds in 12 weeks is not an unrealistic goal. Assuming you're already eating healthy, add exercise to your every day life. Try pilates every morning to become toned in area's where it's hard to get toned in the gym for- like your core and create long and lean muscles. Do you have a gym membership? If so, take advantage of their weights and do some weight training. This will help to give you strong and defined arms (but still feminine). They also may have good core machines as well. Make sure to do AT LEAST 30 minutes of cardio each day, although I would recommend an hour or more if you can. Running is one of the best and doing intervals of walking, jogging and running as fast as you can every two minutes or so inbetween is one of the best ways. This also works on bikes.

green tea is good for burning fat accumulated over many years, is good to dring in the morning, and around the day drink a lot of water and walking around 30 minutes daily, good luck.

drink a green tea, and more do running at the morning and use treadmil, its really-really it works for you, but more burn fat better you must lot swimming , because with swimming you can burn calorie up to 400 kkal :)