I've read many times that you shouldn't try and lose more than a pound a week, and/or that in many circumstances your weight loss goal should correspond to how long it took you to put the weight on. If the weight you want to lose is just baby weight, it should be a little easier to lose it by returning to a higher activity level etc.
I also know that once you lose about 10% of whatever your current weight is, your body starts fighting the weight loss and begins to try to gain the weight back. Your metabolism changes, you crave foods more, your muscles become more efficient so you're burning fewer calories doing the same activities. Be aware of that in relation to the weight you want to lose and the best way for you to stay on track and change your habits in a way that will not only allow you to lose the weight, but to keep it off (assuming that is also a goal).
I do not recommend diet pills unless you dont mind gaining all the weight back once you stop taking the pills. Also, many of them are not particularly safe. You also need to not starve yourself and eat at least the minimum calorie intake for your weight a day. Eating much less will reduce your net loss, but it will only work for a short period of time before your metabolism becomes much more efficient and clings to every bit of fat it can get. And that makes the weight gain even worse, especially when you finally break and eat a proper meal.
Up your intake of water. Drink a glass before meals as it will make you feel fuller. It also helps your metabolism. Cut down on any sugary beverages you drink. Watch your portion sizes carefully. Eating on a smaller plate and with smaller utensils can help trick your mind into feeling fuller and being satisfied eating smaller portions of food.
With working out, make sure you're entertained. Do something that ensures that your working out time is somewhat pleasant. Plan it so you can listen to music that excites you, or can watch your favorite tv show. I'm very in shape and I still can't work out unless I distract myself from the fact I'm working out. I can run 8 miles or so in an hour with my ipod, but if I try without I'm lucky if I get to 15 minutes before stopping. Also, don't be afraid of training with weights. It helps maintain muscle that your body might try and burn off rather than just fat, which often happens when people just diet and do cardio. It even helps speed weight loss because the more muscle you have to maintain, the more calories you burn. You could easily gain several pounds of muscle and lose multiple times that. It may not total your goal loss weight, but you will LOOK like you've lost more than if you didn't put on any muscle at all.
The other thing to remember is to keep gradually increasing whatever workouts your doing. As I mentioned in the beginning, your muscles become more efficient and it won't take as much energy to do whatever it is you're doing.
Love yourself and be confident in how you look, whether the numbers are to your liking or not. People will notice if you look good, but they'll also notice when you seem truly happy. Good luck