Test your current level of turnout by watching yourself do a plie in the mirror. Since turnout comes from the hips and not the feet you will be able to see if your feet are overcompensating for your hips. If your knees are not bending directly over your feet you are overexerting your feet for turnout. Bring the angle of your feet in until your knees bend directly over them. This is your current level of turnout.
Exercise and stretch regularly to loosen the muscles of your hips and legs which will help you increase the turnout of your feet. Lay on your side with your feet extended at a 90 degree angle from your body so you form an "L" shape on the floor.
Wrap a resistance band around your legs and raise the top leg for a few repetitions. Repeat laying on the opposite side.
Sit with your feet extended in front of you. Wrap a resistance band around your thighs and practice repetitions of separating your legs slightly then bringing them back together.
Loosen up muscles by lying on your back on the ground. Place a tennis ball beneath the small of your back. Roll the ball down one side of your rear, pressing down on areas that are tense. Repeat on the other side.
Lay flat on your stomach with your legs extended straight out. Slowly bend your knees to the side to bring your feet in so you are touching the bottom of one foot to the bottom of the other. This will stretch your hip muscles, aiding your turnout.