Women have different body shapes and sizes so, what suits your friend might not suit your body type.
It is important to choose clothes, keeping your body type and cuts in mind. Know your body shape to dress right:

1. Diamond: Your hips are broader as compared to your chest and shoulders. You have a tendency to gain weight on the stomach, back, hips and buttocks. If you feel the need to minimize the waist, then you belong to diamond shape body type. You can make the body appear proportionate by wearing a structured jacket or a poncho can create an illusion of length thereby.

2. Apple: If you have waist which is undefined and high stomach, then your body shape is mostly apple. The main aim is to create an illusion of longer upper body and a drop waist dress, which hits somewhere around the hipbones, or empire waist dresses which have a raised waist can work wonders. Avoid halter, boat necklines as they will accentuate your already-broad shoulders. 

3. Pear: If your bustline is proportionally narrower than your hipline and your bottom is well-rounded, you probably have a pear shaped body. Your main aim is to balance your lower half by creating the appearance of a wider upper body. So dresses which emphasise on your bust will create a balance. A-line dresses emphasise on the upper body while slimming wider hips.

4. Hourglass: Women, who have figure that looks like hourglass, don't have to worry much. You can emphasise on your shoulder and neckline area as your hipline and bustline are the same width and your waist is well defined. Classic cuts and scooped necklines will accentuate your figure.

5. Tubular: If your full bustline and full hipline are about the same width and you have a little waist definition, then probably this is your body type. You have to add curves by defining your waist and shoulders. Dresses that wrap or flow through the waistline with medium to high necklines will help bring out the curves. Stick to knee-length dresses. 

6. Rectangular: If your waist isn't defined and your hips tend to have a similar width as the shoulders, you fall under this category. The idea is to minimise the waist, emphasising on the centre or above the waist. Shift dresses and empire line dresses work well.