Good helmsmanship and hanging on by the seat of your pants.
Your going to have to learn how to see changes in wind direction by using other means. Watch the water for clues, I know its harder on a reach, but you can see the wind. The water will give you clues. It will become second nature after time, more of a feel for the wind than anything else, and very quick reaction time helps. and just so you know, if the sail gets backwinded, its probably already too late. Never sailed a Laser, but grew up on a Sunfish.
Courtney is My Hero
If a man is to be obsessed by something, I suppose a boat is as good as anything, perhaps a bit better than most - E.B. White