You can do it right now!
You will feel your turnout muscles, and feel an easy but deep stretch. Releasing tension will help you increase your ballet turnout.
Stretching exercises are necessary to relieve tension in your muscles, thereby improving muscle tone.
So, sitting on a chair, with both feet flat on the floor, lift up one foot and cross it over the other thigh. Just like a normal sitting position. Next, clasp your hands under your bent knee, and push down into your hands with that thigh.
The feeling is subtle, and a little different. This is resistance stretching.
Different angles: you can turn into the bent knee further, and you will get a slightly different stretch in your turnout muscles.
Turning away from the knee, the stretch will feel a little different.
Do each side. If you have a tighter side, you can always repeat that side again, to get an extra stretch.
Get your own DVD of stretching exercises, beautifully demonstrated so you can learn them all. Here's an interview with the lady who will see when you buy your DVD: