This one isn't so much a tip as much as it is a personal preference to my shooting style. Every photog will have their own set of guidelines they follow to make sure their work stays consistent. Sometimes we have to stray for one reason for another, but we will strive to maintain that consistency. For me, it has to do with a person's eyes. Well...not really their eyes, but the colored contacts that some folks choose to wear.
For the record, this photo does NOT represent one of those such instances. Jena is one of my favorite photo subjects who just happens to be blessed with some very photogenic eyes. There would never be any need for her to wear contacts to alter her eye color. Unfortunately, some people don't feel the same way about their natural eye color and they choose otherwise. To each their own, but it really hurts the quality of any professional photos they choose to have done.
You have all heard the saying that the eyes are the keys to the soul, right? Well that is certainly the case with photography. A person's eyes can make or break an incredible picture. All because your eyes are what gives your picture life. Your emotions come through in what your eyes express. So when a person has on contacts, the eyes look absolutely dead.
Let's put aside the simple fact that colored contacts very rarely look genuine. That alone is an obvious reason to avoid having them in a professional shoot. Then there is the secondary reason (and my personal pet peeve) that contacts don't capture catch lights very well. If at all. If you can't emote through your eyes, then a professional photo of your face is pretty much useless.