As a child, there are few things more fun than sticking stickers on things. Everything(s). Here's how to easily create a peeled sticker effect.
First, you want to start with your object on it's own layer.
Add a background layer by holding [Ctrl] + [Alt] and clicking on the New Layer button at the bottom of the Layers Palette [F7]. Press [D] to select the default colors and press [Ctrl + Backspace] to fill with white.
Double-click on your object's layer in the area to the right of the name. This will bring up the Layer Style dialog box. Click on [Stroke] at the bottom of the list.
Set the Stroke size to something thick for your object, in this case I'm using 6-pixels. Click on the Color box and change the Stroke Color to white.
Click on the [Outer Glow] Style in the Layer Styles list. Change the Blend Mode to [Normal]. Change the color to black.
Adjust the Size and Spread until you get a nice, soft outline. In this case, I'm using a Size of [9-px] and Spread of [35%].
Move on to the [Drop Shadow] Style in the Layer Styles list. Adjust the Angle to [90°] and increase the Distance slightly [6-px].
Press [Ctrl + T] to bring up your Transform bounding box. Before you do ANYTHING, right-click in the box and choose [Warp].
Now click-and-drag the box from the lower-right corner up slightly.
Press the [Return] (number-pad Enter) to apply the transformation.
Create a New Layer [Ctrl + Shift + N] above your object's layer. Then press [Ctrl + Alt + G] to create a create a new Clipping Mask.
Set the Layer Mode to [Screen] and the Layer Opacity to around [50%].
Choose the Gradient Tool [G] and click on the Gradient in the Option Bar (up top) to bring up the Gradient Editor. Edit your Gradient to look something like this:
Click-and-drag your Gradient in a very small area where you thing the "bend" of your sticker should be.
It may take a few tries to get it right.
Right-click on the "f" icon in the right-side of your object Layer in the Layers Palette. When the menu appears, choose [Create Layers].
You will now have a bunch of various Layers underneath your object Layer. Find the one labeled "Drop Shadow."
Press [Ctrl + T] to bring up th Transform Bouncing box again. Right-click and choose [Warp] again.
Click-and-drag the right corner towards the right to bring the shadow "back out."
Reduce the "Fill" on the "Drop Shadow" layer to make it a little less harsh.
And… that's it! Feel free to change the stroke and background colors as you wish. Play around with it. Have some fun.