First, lock your windows layer, and then create a new one; drag this layer underneath your first layer, so that no matter where we place our stars when we’re done they’ll still be in the background of the city skyline. Then use the Oval tool to draw a gradient-filled circle; hold down the shift key while drawing to keep the shape circular rather than oval or elliptical. Draw it fairly large for now so you can see the results of your shading; we can scale it later. Fill it with any blend of color you want your stars to be. I’ve had enough of yellow, so I’m making my stars a pale blue-to-white fade. Make sure that your stroke/outline is turned off.
You’ll notice that on the Color Mixer options is a setting called Alpha. This controls the opacity of your fills or strokes; when it’s selected for a solid fill, changing it will affect the entire section colored by that fill. For a gradient fill, you can affect the opacity of opposite ends of your gradient spectrum, to make a fade-in or fade-out effect. You’ll notice that the default is set to 100%; in order to make the faded effect, I’m going to select the color block marking the white end of my gradient, and then use the Alpha slider to set the opacity to 0%. You’ll see that this will cause the circle for your star to fade out towards the edges.
