The peeling sticker effect looks cool and is one of the easiest effects to do in photoshop. I will show you the steps to complete this simple effect.
Start a 400X400px document and create a black circle that fills up most of the area
Add blending options to it similar to this or whatever you want
After that mine looks like this
Create a new blank layer below that one and merge them together so the blending options will not effect cutting the object.
Use your plygon lasso tool or pen tool to select an edge of the sticker
Use ctrl+x to cut the edge off and ctrl+c to paste it back in
rotate it 180 degrees and fit it back on the sticker
Hold down ctrl on your keyboard and click on the icon beside the layer you just made to create a selection around it
Create a new layer above that and fill the selection with the color white
You can delete the layer below it now.
Zoom in 200% and grab a 65px soft brush and make sure you have the color black as your foreground color
Set the opacity of the brush to around 46% and paint the edge of the layer
Do the same to the lower edge and I am left with something like this
With the selection still made around it create a new layer below it.
Fill it with black and click on the screen to remove the selection and add this gaussian blur to it
Move it with the arrow keys so that the shadow doesn’t show on the white background. Change that layers opacity to 50%.
You can do this to as many edges as you would like.
Next for the glossy portion. Use the pen tool to make a selection like this
Fill a new layer with white in the selection. Use the ctrl+click technique to create a selection around the sticker
Cut the part you want and paste it back in then set its opacity to about 5% and drag it below the peel layer
Add some text and you are done!