Seams

*French seam is a strong narrow seam in which the edges are not visible; usually used for fine fabrics, this seam is sewn twice, first on the right side and then turned in and stitched on the wrong side so that the raw ends of the fabric are enclosed in the seam, leaving a clean, polished, professional look.

Examples:

On real garments.

Tutorial video for make a french seam.

*Tailor's tack  is to transfer  pattern makings to fabric, or to otherwise mark the point where two pieces of fabric are to be joined. A special loose looped stitch used for this purpose. 

Examples: 

How to make a tailor tack (demonstration)

The Hong Kong seam is used when you do not want a lot of bulk along the seam. Therefore, you use a single fold bias strip of fabric (or bias tape). This means the strip of fabric is pressed in half along the length of the strip. A Bound Seam uses a double fold bias strip (or double fold bias tape).

In addition, when using a Hong Kong Finish, the seam allowance will be pressed open. When using a Bound Seam, the seam allowance can be pressed open or sewn together in the binding and pressed to one side.

Examples:

For example in the Christian Dior collection Spring 2014. The designer used hong kong seams on most of the garments.

Tutorial video hong kong finish

References:

*http://www.sew4home.com/tips-resources/sewing-tips-tricks/machine-sewn-seam-finishes-hong-kong-bound-seam-part-4-4

*Youtube

*http://www.thefrenchseam.com

*http://en.wikipedia.org/wiki/Tack_(sewing)