Tadasana is the foundation to all yoga poses. Tada means mountain. In this pose we are as still and firm as a mountain.
Keep the tail bone tucked in and push through the heels.
Make sure weight falls on the feet evenly.
Feel how the breathing causes movement in muscles around the stomach and chest. It is this movement that must be even and equal on both sides. If not the pose will not be steady. This is analyzing cause and affect between the elements of earth and air.