Night Fly Fishing
Many anglers simply pack it in and head for the car too early in the evening. The biggest fish in rivers and lakes feed more at night than in the day. This is especially true of big browns and brook trout.
Fish are also more aggressive and less wary so you can get close and use movement on your flies. It may sound counter-intuitive, but dark flies, especially streamers, that present a good silhouette are often very effective at night. You can fish by feel with streamers, nymphs, or mouse flies, use sunset or moon glare to see your dry fly's silhouette, or even fish by sound with dry flies.
A couple of things to make sure you have are a headlamp and wading staff to get back to the car safely. Also, if you have to cross the water much in the dark make sure you map it out first in the light to avoid unpleasant moonlight swims. Next time you're out for an evening of fishing stick it out for a few more hours. You may be surprised at the fish that come out to play in the dark.