I took this screencap from The Quiet Man, and decided it would make something visually appealing, so cropped it and made a base out of it. I cropped the original image, then duplicated it once and set the duplicated layer to screen. I adjusted the fill of the screen layer to 50%, and merged the two layers into the base. I've been doing this to every icon I've made for the last week or so, as it gives me a little bit better control and functionality in what I want to do later.
I took the base and ran it through sharpen twice -- on the second time, I went to Edit>Fade sharpen, and adjusted it to 50% on the normal blend mode. That gives us this simple base.
I duplicated the base once and set the duplicate to soft light. It looks like so.
I created a new layer between the two bases, and did a gradient fill with one of Photoshop's default pastel gradients -- green, purple, blue -- and set it to pin light. That looks like so.
Now it gets fun -- on top of the second base layer, I did another gradient, in Photoshop's yellow, pink, purple pastel gradient, and set it to hue.
On top of that layer, I created a new layer and did a color fill in #02106c, and set that to exclusion at an internal fill of 64% -- that means adjusting the "fill" option instead of the "opacity" option in your layers menu. It looks like so, with that adjustment:
I selected one of the yellowish tans from Mary Kate's dress, and used one of

I went back and duplicated the exclusion layer from before and dragged it to the top of the layers, *over* the cloud layer. Then I adjusted the fill just a little more to 42%, which gave me this:
I created a new layer and used the same tan from the cloud layer to do a diagonal scanline brush texture. At 100% opacity, I did the brush, then set it to soft light, and reduced the internal fill of the layer to 20% -- it's just barely there, and yet gives it a hint of texture.
And, last but not least, I used one of my latest border brushes and, in a new layer on top of everything else, used -- again -- the same tan, set to soft light at 100%. All done -- you have a nice, soft, pretty icon.
The following brushes were used in this tutorial: