Developpe help please?

I used to have a similar problem, but with my grande jetes. For holding your turnout make sure you're using the same muscles you would in a plie where you are turning out properly and your knees are 100% over your toes. You may need to strengthen those muscles before it's going to be perfect. I would just try to think of relaxing and not trying to get your leg too high before you work on making it correct. Also, you may want to stretch before-hand so that your legs feel looser before you developpe. Just keep trying!