Learn the meaning of turnout. In ballet your legs and feet must always be turned out, meaning that everything should be pointed outward. Aim to have your feet, thighs, and knees facing the side walls. Your right leg toward the right wall and the left leg toward the left. Try to turn everything out from the hip all the way to the end of your toes.
Practice demi plies. Stand in first position (heels together with your feet turned out) facing the side wall, holding the barre with your left hand. With your arm also in first position (almost straight down, slightly bent at the elbow, with your hand cupped inward, lightly touching your thigh) bend your knees about half way down to the ground. Keep your turnout. Make sure to keep your heels on the ground as you bend. Return to the starting position. Repeat five times for strength building and practice.
Learn the tendu. Stand once again with your feet in first position and hold the barre with your left hand. Put your right arm in second position (straight out to the side from the shoulder, elbow slightly bent, and hand slightly cupped inward.) Your body should be facing the side wall again, not the barre. Leading with your heel, slowly slide your right foot directly out in front of you, through the ball of your foot, until you are only touching the floor with the tip of your pointed toe. Slide the foot to the starting position. Repeat five times for strength building and practice. Turn your body around to face the opposite wall and hold the barre with your right hand. Repeat this step using your left foot.
Learn the battement frappe. Begin in the same position at the barre as the tondu. This time brush your foot, leading again with heel, off the floor to a pointed toe, and back again quickly. Repeat for strength and practice. Turn your body around and repeat this step with your left foot, holding the barre with your right hand.
Perform a grand battement. Begin in the same position at the barre as in the previous Steps. Keeping your turnout, brush your right foot quickly in front of you, off the floor, as high as you can leading from the back of your thigh. Keep your leg straight. Return the leg back to first position. Once again repeat to build your strength and your flexibility. Turn around and repeat with your left leg.
Continue practicing these exercises and soon you'll find your flexibility improving, your feet and legs getting stronger and stronger. When performing leaps across the floor these exercises will help you achieve greater heights as well. See Resources for more exercises.