What are some exercise and diet tips for a bigger and a smaller waist ?

You should embark on some weight training in a well equipped gym or health club. The is mostly fat covering the gluteus maximus muscles so you want to increase the size of these muscles but not increase too much fat. Full squats using weight on the shoulders is the best exercise for the glutes. For the chest do bench presses (flat on a bench) and declines on the decline bench. For 5' 2" you are already a little heavy so stay away from fats, esp deep fried food and eat more protein to put on muscle. BTW, muscle is heavier than fat and burns calories while fat doesn't.