It’s necessary for the beginning to create a new file (File>New) of 512x512px and 72 dpi. Select the Ellipse Tool (U) and try to make an ellipse like the next one: Fill 0% on the layer: Select Blending Options>Gradient Overlay (making a mouse click on the processed layer on the layers’ palette) setting the next demands as below: This element we should get. It’ll represent the shadow of the icon: .