I agree with most things said but just wanted to add this. I think you need to learn more about posing, and lighting in direct relation to how it can flatter your subjects or make them look bad. The above image is a good example of how by not posing the woman properly, her neck looks really big and unflattering. A slight change to the angle her head is pointing (as CC said) and also by getting her to push out her chin and down (elongating her neck) would have helped here.
There are some really good posing tutorials on you tube. Good luck.