To move an active layer one pixel at a time in Photoshop, you can use the arrow keys on your keyboard. First, make sure the layer you want to move is selected in the Layers panel. Then, use the arrow keys to nudge the layer up, down, left, or right by one pixel at a time. Press the up arrow key to move the layer up by one pixel, the down arrow key to move the layer down by one pixel, the left arrow key to move the layer left by one pixel, and the right arrow key to move the layer right by one pixel. This is a quick and easy way to make small adjustments to the position of a layer in Photoshop.