Start from the feet and move up...

Pada Bandha

Stand in Tadasana(Mountain Pose) and look down at your feet.
Bring them under you the width of your sit bones(not the outside of your hips) just about a fist width apart and make them parallel to each other. (If you bend your knees and they do not go straight forward, but instead knock against each other or move away from each other, then adjust your feet so the knees can go straight forward.)
Bring your weight evenly into the ball and heel of both feet, the inner and outer edge of each foot, and into both feet evenly.
Then lift your toes and reach them away from each other. This action should engage the muscles in the arch of the foot which is Pada Bandha. Make sure you are still grounded into all four corners of your feet keeping the weight stabilized as above.

Sit Bones

Reach your toes forward and place them down on the floor or mat. Be careful not to grip with the feet, but just lengthen and lift. The engagement in the foot should not create a cramp. Your feet should still feel supple.
Feel how aligning the feet in this way engages your leg muscles and puts the rest of your body into alignment. Do not lock the knees and if you find tension anywhere in your body try to release it.

Practice this alone on your mat, in line at the supermarket, or brushing your teeth. Allow it to become a part of the way you stand in daily life. On your mat practice this with the breathing exercise for Mula and Uddiyana bandhas in the last post.