I guess the simple answer is try not to rush it (easier said than done, I know!).
Try lifting the foot and gliding backwards for a few seconds (without attempting to turn your body) before you start to turn your body. It makes sure you have the balance on one foot first. Then pick something to your left or right (depending on which way you're turning) to look at and focus on, then turn your upper body to look at it, then put the foot down.
This is what worked for me anyway. I was finding it quite difficult, then one of the coaches kind of explained it this way. There's a cafe at one end of our rink and a clock at the other, and when we were skating across-ways, the coaches would say "lift the foot, now look at the cafe/clock, and...turn". Worked for me anyway. Hope it helps a bit!
