Two of the important ingredients for a pirouette are balance and preparation. But its important to have these two at the same time for consistent pirouettes. In your preparation, try to already be on balance and maintain it as you plié for the preparation. It may seem obvious, but some dancers disconnect the two, the balance and the preparation step, thinking that the balance only happens once they releve and begin turning.
A great tip to improve your pirouettes is to get into your preparation and hold it for 8 counts, really trying to feel that you’re in a strong position and most importantly, on balance. Then, try to do a double pirouette maintaining the strength and balance in your legs.