Whether one is a new yoga enthusiast or one is an old hand, it pays to remember where one can make mistakes while practicing yoga.
1. Do it mindfully, focus: The very essence of yoga is yoking. In other words, yoga is about yoking or union of mind and body. Other than the physical aspect of exercise, yoga is essentially a spiritual practice too. Yoga increases the steadfastness of the mind when done mindfully and with absolute coordination between mind and body.
2. Less is more: Yoga can be customized and modified approximately to suit one's body and it's flexibility. Some people are flexible and nimble while some are stiff with more rigid body.
Do not overdo the stretching bit just because your instructor is doing so.
3. No push, No rush: Do not let your instructor push too hard into a difficult and a risky posture. It might suit her or him while it might impact you in a different way altogether.
4. Be careful when doing breathing exercises: According to certain references, when certain advanced pranayams are done with out following the instructions as required, then these can result even in impaired memory and in worst scenarios can even cause memory loss.
5. Take small steps first: Enroll for the beginner's class before boldly joining advanced classes. Else face dissatisfaction or an injury.