1. Stop worrying about it
2. Watch Sensei's feet
3. I find that I pick up less when I watch and think about it at the same time, and I'm generally in real trouble if I get up feeling really confident, like I *know* exactly what I just watched.
4. Expect not to know exactly what to do and keep paying attention when nage does the technique on you.
5. And don't worry about it. That makes it much worse - I know from experience!