The way in which a dancer presents his or her feet is very important, especially when it comes to choreography.
Whenever a dancer presents their feet, the heel should be more forward than the toes. Whether your foot is to the front, side or back, your foot should still follow the same rule and line.
Training yourself at the barré to continue to have the same form with your feet will show through in choreography. No matter what angle your feet are at, you should have energy coming through your big toe.