In the video below my mentor Rachel Cosgrove makes a great presentation to a group of females about the 3 breakthrough's needed to change your shape. Rachel was doing this talk as a tour for her great book The Female Body Breakthrough.
Rachel makes 3 points that need to be in balance for you to reach the shape you are after, Mindset (having a goal), Exercise (resistance training) and Nutrition (sensible eating and lifestyle changes).
If you have these 3 breakthrough's in balance you will not only change your shape but also keep these changes for good!