1. Open your photo and duplicate the background layer (Ctrl + J or Cmd + J).
2. Add a new blank layer, between the two layers. To do this, simply hold down your Ctrl / Cmd key and then click on the New Layer icon at the bottom of the layers palette.
3. Fill the new layer (Layer 1) with black. Press D on your keyboard to set black as your foreground color and white as your background color. Now, using the shortcut Alt + Backspace (Win)
4. Add a new blank layer between the black-filled layer (Layer 1) and the copy of the original image above it.
5. Select the Rectangular Marquee Tool and drag out a rectangular selection as the inside of your first polaroid.
6. Fill your selection with black as we did before using the keyboard shortcut Alt + Backspace (Win) or Option + Delete (Mac).
7. Now we have to create a clipping mask from the filled selection. Click on the layer above ("Background Copy" in your layers palette) and then go to the layer menu at the top of the screen and select Create Clipping Mask (or use Alt + Ctrl + G (Win)
8. Add another new blank layer above the black filled layer (Layer 1) using the icon at the bottom of the layers palette.
9. Having the Rectangular Marquee Tool still selected, drag out another rectangular selection as the border of the polaroid.
10. Having your new blank layer selected (Layer 3) and since white is currently our background color use the shortcut Ctrl + Backspace or Cmd + Delete to fill the selection with white color. Then you can deselect the selection. Now we have our first polaroid image.
11. Next let's add a drop shadow layer style. Select drop shadow from the Layer Styles icon at the bottom of the layers palette or going to the Layers menu at the top. I set my angle to about 120, then lower the opacity to about 35% and leave the rest standard. Click OK to apply the changes and exit the Layer Style dialog box.
12. Select both layers which make up the polaroid (Layer 2 and Layer 3) by holding down the Shift key and then using the shortcut Ctrl + T or Cmd + T bring up Free Transform and rotate the polaroid. Then you can move the polaroid to a new location.
13. With these two layers selected, hold down your Shift key again and add the "Background Copy" as well. Now all three layers should be selected and highlighted in blue. Use the keyboard shortcut Ctrl + G.
14. Now duplicate the layer group.
15. As we did with the original, we are going to move and rotate this second polaroid using the Free Transform. So, open the new layer group and select the bottom two layers, holding down the SHift key. Then Ctrl + T to rotate and move the selection to a new location just as before.
16. That's basically it. Now add, move and rotate more polaroids as needed. When you are happy with the result Flatten the image, save and you are done!