How to flatten my abs?

Ok here is my situation……I am 5'0 and 115 pounds. I lost a lot of weight a bit back. As a result of the weight loss and previous 2 pregnancies I had a lot of loose skin on my tummy. I had a tummy tuck this summer and am happy with the results except for one thing. Even though I am a healthy weight and have taken care of the skin issue I still have a "round" tummy. Imagine a little kid tummy…hehe. I would really like to get it nice and flat. Can you suggest to me some exercises to get that "pulled in" look? I would really appreciate it! Thanks!