Please note that holding Shift while using the arrow keys to nudge always
moves by 10 pixels, no matter how far in you’re zoomed. Also, dragging
points with the mouse will snap to pixels in most situations—most, but not
all.
While not perfect, this technique does remove some of the frustration with
editing detailed vector paths in Photoshop. Or maybe it’s just another
reason why complex shapes should be drawn in Illustrator first, and then
pasted as shape layers?
Take Charge Of Your Pixels
Using the correct techniques, it should be easy to place pixels exactly where
you want. Remember, you’re the one in charge. Demand that they fall in
line. Accept nothing less than pixel perfection.