During asana practice pay close attention to the alignment of your body, weight distribution, breathing and honesty of your effort. And even though you might feel your postures are not done perfectly, it does not matter. You do not have to become a contortionist over night. In time you will be pleasantly surprised at how much easier the positions become once you understand the mechanics and develop more flexibility, strength and balance. It is a good thing to focus on how much better you can do the postures compared to how poorly you did them before you applied the proper techniques. It is very important to compare your practice to yourself from time to time to see progress made.