General selection of the part you want to be tear
Before you start step one, lets set the document. I chose 350px on 350px but you can choose any other size or apply this effect on images web graphics.
Open a new layer (Layer>new>layer), select the Lasso Tool (L) and start make a selection (not straight) through an imagined diagonal.
Next, you need to pick the color, I picked #525252 (double click on the correct foreground color and then enter this value where the '#')
Paint the selection you made with the Paint Bucket Tool (G).
Open a new layer under the top one so the order will be like below:
Now, you should repeat the first steps and make a new selection
Paint it in #999999 (also explained in the above steps).
Blur the pixels
The result till now should be like this:
You probably can see the pixels.. your goal is to make the pixels a bit blurred and it will look better.
This will be done with the blur tool.
After picking this tool, a top bar of this tool will be shown. enter the below values to it so it will be easier for you to blur it.
When you're done with the values entry, pass on all the pixel parts in both layers. don't do it too slow but also not too fast.
If this is too blurry, you can also go back in history or choose the 'sharpen tool' and pass it on once again till it's perfect!
The result should be about like this:
Lighting effects
The torn paper effect is ready but for making it a neat effect, lighting effects are required.
I used two tools for making the lighting effects, 'Burn tool' and 'Dodge tool'
Start use them at the 'paper edge'. one more tip is to change the brush tool.
Here's my final result:
