Bring a flashlight, but not too bright, just enough to see what you are doing when changing a fly. TURN YOUR BACK TO THE RIVER when you turn it on!
Make sure you have plenty of insect repellent!!
Don't be afraid of the bats, they won't run into you. Just try not to hook one!
Wade slowly, once it gets dark you can't see what's in front of you, such as holes, logs, rocks, etc.
Have a good stash of Hex patterns, and be sure to bring along some Light Cahills or White Wulffs in size 12, as a white Stenacron (used to be Stenonema) hatches around the same time as the Hex, and if there aren't many Hex on the water (it is highly variable from night to night), trout WILL feed on those "little white ones", as my old flyfishing mentor Terry Sharik used to call them.
Use heavy tippet after dark, like 2x or even 0x. Fish can't see it well at night and some fish will be LARGE, and the heavier tippet turns over the big #6 Hex patterns better, as they have some air resistance. Put on a good fresh one too, big fish will find all of your bad knots.
Be prepared to LISTEN for fish because eventually you won't be able to see anything.
Best hatches are on dark, humid nights, but as I said above, they are somewhat unpredictable. One night it is just raging, and then the next night nothing...
BEST OF LUCK! I hope you get on some really nice ones out there as this hatch does bring them up. I also hope you get to actually see a mating swarm, it is quite spectacular and they make quite a buzzing sound. I walked into one once, and they just parted for me and closed back around once I was in the swarm. VERY cool. One night I also got to see them flying in front of a waxing gibbous moon, their gossamer wings lit up like diamonds...
Oh, and don't be surprised if you feel fish run into your legs. I am NOT kidding! When this hatch is on for real, fish lose their minds, like rising less than a rod length in front of you, and bouncing off your shins!
Tight lines, and no breakoffs! And we want PICS!!
No matter how big the one you just caught is, there's always a bigger one out there somewhere...