1. First, find a photo that you want to make into a magazine cover.
2. Now, just add all the things that are on magazines (title, articles w/ page numbers, date, price, barcode). You can also add text boxes. To do this, create a new layer and use the Rectangular Marquee Tool to create boxes. Fill them with a color you want, and lower the opacity of the layer to see the background. Then, merge this layer with the photo.
3. Go to Image> Canvas Size, and increase the canvas size a little to have some room to warp your photo in the next steps.
4. Edit> Transform> Perspective. Adjust the photo so it looks like it's laying down. You may have to scale down the height so it doesn't look too stretched out.
5. Edit> Transform> Warp. Warp the photo so it looks like the cover of a magazine that has been flipped through a few times.
6. Duplicate this layer. Repeat step 5 on the lower layer to make it look like the bottom page of the magazine. Now go to Image> Adjustments> Hue/Saturation, and lower the Lightness to 0. This will turn the page black. Repeat this step again, but this time increase the Lightness to make it a shade of grey.
7. Repeat step 6 to add a third page in the center.
8. To give the look of many pages, merge all the layers together, then select the bottom edge of the magazine with the Polygonal Lasso Tool. Then go to Filter> Filter Gallery> Artistic> Underpainting. Adjust the sliders to create horizontal lines that will look like multiple pages.
9. Right-click on the magazine layer in the Layers Palette and select blending options. Select Drop Shadow, and adjust the sliders to get the shadow effect you want.
10. Finally, I just moved this layer onto a photo of a table top.
