Start with your legs stretched out in front of you, while sitting. Slowly start to lengthen your ankles. You may find that your toes start to go out. You may also find, at first, that you try to squeeze your whole legs. Work on feeling just the extension in the ankles and feet. Avoid pressing down with the feet too strongly, as this will make the foot curl rather than lengthen.
Work on extending the ankle more – you want it to continue the line of the shin and not stop at an acute angle. Remember that the toes should lengthen, not squeeze together.
Next, stand up, and with a leg stretched in front of you, work on maintaining that long foot and ankle. Do this with the leg to the side also. Stand near a piece of equipment you can balance on. Do not allow your body to become unbalanced, tense the shoulders or the knees, tighten your breathing, or lift the hip on the side you are extending the leg on. Keep the body standing up nicely, while you concentrate on the foot. If the body position changes, take the leg down lower until it feels controllable.
Check your foot in the mirror. Look at the toes and ankles. Are they different? Is one foot rolling in on the ankle? This is an easier thing to work on in a standing position. Once this is controllable on one side, do the other side. Check this in the mirror from the side and from the front.
Continue to make sure that the thighs, knees and hips are all controlled and quiet, and not stiff.
Once you can feel this in the feet in these positions, you can add more movement around them. Start with a balance position and work on having the foot prepared while you slow the position down as you prepare. Do it to counts if necessary, or to music that has counts in it. Work on feeling the shape of the feet, not only at the top, but when the leg comes back to the floor. Work with a bar if this helps.
Once you can feel the foot line well in a balance position, try doing this in a jump. Prepare the line as you prepare the jump. Then see how well you can keep the leg and foot in that shape as you are airborne, coming down in a landing. If the foot falls apart at the moment of jumping, then the shape of the feet is probably okay, but integrating them into all of the positions you need is the next step. The key is to prepare the foot in advance so you don’t have a late extension in the air or have the feet fall apart on landing. But make sure the legs are not stiff in the air, and that you can land quietly with knees and feet absorbing. If you find you can keep the shape of the feet, but not the legs extended, focus more on the whole leg line. The foot extension should be so that you can absorb a landing on it and still feel free in the leg.
Practice this in different types of jumps, or with simple combinations in floor.
When is your foot in the best shape? Extended in a position? Preparing a balance? Or jumping? You can use these three ideas, being in a position, preparing for a balance or in a small jump or leap, to test the quality of your feet as you train.