A way of duplicating layers when working on a busy composition in Photoshop
To duplicate a layer in a busy composition hold Opt/Alt, click over part of your image using the Move tool, and then drag it across the canvas.
Make sure the Move tool is set to Auto-Select: Layers in the Options bar first.
You can of course go to the layer inside the palette and press Cmd/Ctrl+J, but it can sometimes take more time finding the layer and can be guesswork.