Let go of attachments to poses. It's very easy to see lots of pictures on Instagram, or to look at someone else in class and I think, I'm not doing this right I need to be more flexible/strong/get my toes in my mouth...
So long as you have followed the cues the teacher has given you and you are feeling something in your body that isn't painful then that is enough. I always like to say to work at a level 4 on a scale of 1-10. Level 4 where you are feeling sensation, enough to keep your focus on it, but not so much that it's uncomfortable and you are in pain.
A teacher cannot always predict where there might be tightness in your body as everyone holds themselves in completely different ways. Part of the practice is becoming more in tune with your body and what's going on with it, so take it step by step, following the cues and listen each time, not just to the teacher, but to you.
PS. Anyone have any idea where my left hand went in this picture?! Me neither!