Well first you must understand what exactly is a butt!!! Number of muscles, 2 major ones to concern with, the others get involved too. Gluteus maximus and gluteus medialis. Both tend to be problem areas for women, more fat storage as opposed to men getting a gut. Plus sometimes the blood flow in these muscles can be poor, so even if you lose a couple of stone, you could still have a big butt!!! This is because the area is inefficent at transporting the fatty acids, so its takes it say from the waist. Solution? you need to improve the blood flow, how? the correct exercises, say, romanian deadlifts for the gluteus maximus, hams, erectors. Lighter weight, higher reps for women with ultra strict technique. The gluteus medialis sits higher up and controls abduction, so any decent abduction exercise, machine or body weight excellent. Finally the inner thighs, another problem area for women, adduction movements fine.
Leg/Butt routine for women
Squats (slightly wider foot stance, to hit butt/inner thighs more)
Stiff legged deadlifts
Seated machine hip abductions/adductions superset
It depends on the type of your body. Everybody has unique type of physiology and needs individual diet and lifestyle. Ayurveda is ancient science which can help to identify body type and recommendations for your type not in generally. What is healthy for you maybe not so healthy for another person. It is also important to know what time to eat each food and how to prepare it. You can ask question about yourself though I can`t indentify you type of body exactly without observation.
Eating small meals every three hours that consists of fresh fruits and vegetables, complex carbohydrates, and proteins along with drinking tall glasses of water helps keep my metabolism working at fast speed.