Abt my diet???

im kinda on a diet. i eat special k cereal in the moring w/ a gl of tropicana oj. at lunch i drink a lucerne strawberry smoothie (some fat). then i eat home cooked food. go on the treadmill for 30mins and do squats, situps. then again maybe eat special k cereal (sometimes) or a healthy apple snack bar. am i doing ok??? plz tell me i hav to slim down for graduation. if u hav any other suggestions ill take all of em!!!