From Tadasana (Mountain Pose), inhale to lengthen your spine, then exhale to hinge from the hips to fold. When the pelvis drifts back in this pose in yoga class, the teacher often will come by and gently push it forward to align the legs perpendicular to the floor. When the teacher walks away, the pelvis tends to drift back again. Correct this yourself by gently pressing the fleshy part of the big toes into the mat, which can help bring your femurs into a more upright position over your ankles. Then press the outside edges of your feet into the mat to activate your arches. You should feel grounded. Hold for 5 to 10 breaths before returning to Mountain Pose.