Quick Belly Toning Exercises?!?

I am targeting my stomach. I am already at a good weight for my height, age and gender but I'm not the most toned person in the world. especially in my stomach. it's sort of squishy and I want to tone it up in time for summer! I don't want a manly looking 6 pack but enough that doesn't make me look weird wearing a bikini. so how can I get a toned, hard stomach fast? I already am changing up my diet, cutting out junk, and drinking water instead of soda. so please give me some exercises that target toning my belly. thanks!