How to get a bigger buttocks, larger breast and curvier hips naturally?

You can't: The size and shape of your buttocks, breasts, and hips are largelly determined by genetics, diet, and to some extent exercise. Women tend to get bigger breasts and hips as they gain weight, but not neccessarily in the shape that you want. Likewise, exercise can improve your overall body shape, but not breast shape, etc. In general, eating well and staying fit will make the best of what you have.

Other than...: Weight gain, the only other option would be surgical fat transfer to the hips and buttocks, and either fat transfer to the breast, or breast augmentation.