Easiest ..... Drain the tank down and pick it up off the sand LOL. Maybe not the best way. I've had the most luck with waiting until they're sleeping at night, blast them with a flashlight and net them while confused.
Unfortunately in my 400G tank this has proven on multiple occasions to be the "easiest" way, especially with a lot of rock work. The bigger fish I usually can net with no issues, it's the small to medium sized ones who hit the rocks the first sign of a net in the tank.