How can I improve my turnout?

You have the turnout you were born with. You cannot change what you have. Turnout comes from your hip rotators which is joint. You can open your hips by doing the butterfly and the frog, but never force it or you will have real issues with your knees. It is possible to be born with great turnout and not be able to use it. You must learn to engage what turnout you have. You do this by using the muscles deep within your hips and pelvic floor. Almost everything at the barre is made to help you engage your turnout if done correctly. Especially rond de jambe a tere. Always wrap your thighs outward as well.

If you could put your knees flat on the floor as the other answer suggests, you would have to be born with good turnout. You may never be able to do that, but even if you could, that doesn't guarantee that you will be able to engage it. If she can do that, she was born with good turnout and didn't get it from doing that. She just learned to open her hips up which is not changing your turnout she was born with.

Just try to work more consciously at the barre and make sure you are taking 90 minute ballet classes that includes a 45 minute barre as part of every class.

lay on the ground and go inot 2nd position, then try to make ur hips lay flat on the ground

do this for a couple months and youll have a painless perfect turnout like me