Darts

Darts are folds while are sewn into the fabric. They allow the garment to be more 3D and are essential in giving figure enhancing properties to garments. They are commonly used in womens blouses with two types being used:

Vertical Darts: These are sewn from the bottom to the bust to pull the garment in and towards the waste.
Bust Darts: These are triangular shaped folds which are sewn just under the bust so the material does not hang below.

French Dart at an angle.

                                                                 H Dart below the bust.

Arms Eye Darts: These are similar to buzz darts but are positioned lower down on the garment and are sewn at less of an angle

Centre Front Darts: These change the grain and shape of the centre front of the garment as a new seem must be cut in the middle. It allows the fabric around the torso to be pinched tighter to the body.

H Darts: H Darts are linear darts often used above and below the bust line to tighten the garment in places and allow for room in others. The same idea can be applied to other parts of the body.

French Darts: These too are bust darts which start from the side seem and angle up towards the bust. The dart goes against the grain of the fabric which is why extra care and reinforcement is needed to that it does not lose its shape.

Irregular Darts: Irregular darts can be placed in any part of the garment at many different angles to change it's shape.

Princess Seam: These are curved seems used in blouses and dresses which allow the garment to adhere to the body over the bust or hips. They usually start at the underarms and run as far as below the waste depending on the garment.

Armani 

Here, flowing material covers the princess seams but we can see how the jacket fits the body creating a more curved garment necessary in womens clothes.