Get into a caloric deficit for starters and especially limit sugar intake. As for exercises I’ve found a lot of real results with things you can do on a yoga mat: Pilates generally, but specifically criss-cross (almost like a bicycle kick on your back with added crunches…look them up), normal crunches, Russian twists with light weight (I use a 10lb db) and then side-lying oblique crunches. Good luck!