If you stick to a good diet, eat healthy, get plenty of exercise etc then you should be able to loose at least 2 pounds of weight in a week.
So in 30 days you should be able to lose a total of 8 pounds of weight in 30 days by sticking to a good diet, eating healthy and getting plenty of exercise.
Try walking whenever possible because all that walking adds up to help burn calories and also watch your calorie intake as well.