While Prasarita Padottanasana is straightforward enough, one question many face is how far apart to set the feet. The distance between the feet is primarily dependent upon two characteristics specific to the individual practitioner: flexibility and height. If the hamstrings are so long and/or the stance is so wide that the crown of the head reaches the floor, then the feet should be brought closer together. If the head is nowhere near the floor because of tight hamstrings, step the feet an inch or two further apart to take some of the stretch out of the back of the legs.
Mindfully lift through the arches of the feet and the adductors of the inner thighs as you hold your weight squarely on all four corners of both feet. Be sure that the outer edges of the feet are parallel to the short edges of your mat and keep the quadriceps working to lift the knee caps. Let the muscles at the base of the neck be soft, using the spinal extensors, bandhas, and sides to progressively bring the crown a little closer to the floor with every breath. If a connection is made with the hands to the floor or part of the body, as in positions A and D, use the arms to deepen the posture and keep the energy circulating.