It is more important to achieve proper alignment in a pose than to sacrifice the alignment for the look of the pose. This also means that we will be constantly adapting our poses to fit with our current strength and ability as it increases through practice, as well as modifying for injury, fatigue or lack of practice. Approach all poses in a systematic way that concentrates on proper alignment.
Pain is wrong
It is nature’s way of telling us we need to modify what we are doing. Strong sensations in a stretch leads to muscle resistance which reduces the muscle’s ability to relax and be properly stretched. To ignore pain or strong sensations is to invite injury. Less is truly more when it comes to sensation in stretching. A proper stretch sensation feels pleasant.