Quickly Isolate a Layer

Here’s a trick for quickly toggling the visibility of just one layer in the Layers palette:

Control-click the eyeball next to a layer to make it visible and hide all other layers. Control-click a different layer to make that layer visible and hide all the others. To show all layers you must Control-click and choose Show All Layers from the contextual menu that appears.

Quickly Isolate a Layer

These same tricks work for Locking layers as well.