It's not easy, and I've only recently started to feel stable with my backwards CW crossovers. A mistake many make is to go too fast. I did it, and I see others doing it. You end up losing control. I recently got a young lad to slow down and he then started to do them properly. Try standing still, and then walking sideways by crossing for example your right leg over in front of your left, then moving your left leg behind the front leg and so on. The aim is to get used to the sensation of moving your legs in an unnatural way, and learning to balance. You can also try going round at modest speed and moving your legs to more and more extreme positions without lifting your feet. That gets you used to balancing in positions you don't normally get into. It also stretches your muscles and ligaments and gives them a good work out. The next step of course (no pun intended) once you get the hang of that is to lift your feet off the ice.
Incidentally, I think crossovers are an intermediate skill, and they took me months to learn and I'm still regularly working to improve them. Even when you can do crossovers, you need to learn to balance on the edges properly, and keep the blades flat. I have a friendly speed skater to tell me I'm doing them wrong.
I often see people who should know better doing them poorly. And yes these are hockey skate wearers, the figure skaters tend to have better technique.
Anyway, in the end it's all about getting onto the ice and having as much time as possible practicing, and getting it all wrong until eventually it starts to fall into place. Have fun.