1.The most obvious is the C pattern being slighly "off" or odd. Or something just not right about the printed signature pattern. I have even seem really bad fakes where the CC actually looked like GG. (No this does not mean it is a Gucci instead!).

2.The material is getting harder to spot because a lot of fakers are using the actual material used by Coach so you will need to inspect the stitching and hardware. All of the hardware should be embossed or logoed.

3.The zippers should carry the YKK on them. This is the highest quality zipper. A minor detail the knock-offs will most likely miss.

4.The stitching should be even, trim and neat. Missed stitches, uneven stitching or loose stitching are all signs of fakes. The strict quality control Coach insists on would never manufacture such types of merchandise.

5.Serial numbers are stamped on square patches of leather and usually have a series of letters and numbers in them. The SN will also appear in more than one place usually on the outside and inside.

6.The bag looks similar to the ones in major department stores but are not quite right. OR  The dimensions are off slightly. Perhaps 10-5/8" instead of 10-3/4. These are most likely knock-offs.