Here is how I go about practicing…
Take it as a given that your body is as capable as anyone else's. Work on your mind to really believe that fact and keep the faith in times of discomfort. Short of surgery or a transplant, your body will never look like or behave like anyone else's. You have your own joints, muscles, bones, strengths etc. Work with what you have.
Know your own weakness, we all have them. Don't focus on it - be aware of it. Make modifications or slow. Observe but don't berate yourself.
Understand the difference between discomfort and pain. If something is painful, come out of the posture immediately. Rest. Make an adjustment or modification that you know works for your body. If something is uncomfortable, it is probably the place that needs the most care and attention. Work at it. It will become easier.
It sounds obvious but talking or whispering is really distracting for everyone in the room.
In saying that…
I love questions and chances are if something isn't making sense to you then, there are others! We're all here to learn and questions are the best feedback a teacher can get.
Stick to your mat.
Someone beside you might look like ‘they’re doing it wrong’ but you never know what it is they are working on. There are as many postures as there are bodies. Focus on the posture fitting your own body and not the other way around.
If this is your first class ever, for a while or if it has just been a tough day - give yourself a break. It's a lot to take in in one go. Focus on one thing to begin with and let whatever is not making sense wash over you for today.
Have fun. Laugh. Fall down. Laugh again.