About alignment: Always work with other Yoga teachers, even after becoming a certified Yoga teacher. It helps you learn new things, creates valuable contacts, and keeps you sharp. Find the best Yoga teachers in your area to learn from, work with, and possibly work for.
If you are far away from a Yoga instructor, mirrors are the next best thing, because they help you see your asana alignment, but sometimes Yoga without a knowledgeable assist is like cutting your own hair.
With the aid of mirrors you could develop your knowledge of alignment.
If you have a Yoga friend who has knowledge of posture alignment, you can both make progress together.