As a nurse I get asked this question a lot. Every single person's ody is different. However the design of function is very similar. First take the weight you want to be...lets say for example...150ils. Then add 1000...that's how many calories you need to consume a day to maintain that weight.
Losing weight is about balancing diet and exersice. Limiting sugars and fats, adding fruits and vegitables, and portion control. A lot of people don't realize what true hunger actually is. You know when your stomach growls...that's true hunger. My motto is eat to live...if you eat till your full you getting way more calories then your body needs. So natrually it stores it as fat.
Now exersice. Experts recomment keeping your heart rate elevated over 30 min. in order to lose weight. Doing this a couple times a week is not only beneficial to losing weight, but keeping your heart and lungs healthy as well.
Make sure to get enough sleep. Drink a lot of water. Take your vitamins. Do things you love, find what works for you. Eat a few small meals a day rather then 3 big ones, (Your metabolism is like an engin, too keep it running on high you need to keep it stoked.) Also remember to talk to your doctor before you start any exersice program.
You can do it! Be strong and focus on little goals that add up to your main long term goal.