Whether you are dancing, skiing, skating, surfing or doing yoga, you need concentrations, strength, and skill to move successfully from standing with both feet firmly planted on the ground, as in Virabhadrassna I, to floating freely, balanced on one leg, as Virabhadrasana III. Eventually, this movement will become an effortless flow, but it can be easier to learn if you pause halfway between the two postures to gather your strength and focus. At first you may also want to use a wall to help you balance. By helping you stabilize, a wall can make it easier to focus on building the strength you began cultivating in Salabhasana, and on developing an awareness of the position of your hips and shoulders.
Once you have practiced Virabhadrasana I on both sides, move to a wall. Stand just far enough away from it so that when you bend forward 90 degrees at the hips and stretch your arms overhead, you can place your palms flat on the wall at the same height as yur hips. Check to see that your hips are directly over your ankles, so your legs are exactly perpendicular to the ground. Then return to standing upright.
Leaving your right foot where it is, step your left foot back into postion for Virabhadrasana I, then bend your right knee and take the pose again. From here, you’ll move through the transitional position and then into Virabhadrasana III at the wall before repeating all three positions to the side.
To come into the transitional position from Virabhadrasana I, exhale as you bend at the hips to bring your torso toward your right thigh, squaring and leveling your hips. Keep your legs stable, bending forward until your lower ribs are almost resting on your thigh and your arms are at about a 45 degree angle to the floor. Make sure your breath is full and even and that the bandhas are fully engaged. Hold this position for five to 20 breaths, building strength and stability.
ref: yogajournal