Now on closeup you might see why using the pen tool to make your rips might be a little hard. The cuts look too clean and artificial no matter how many zigs and zags you throw into the path to make it look naturally.
You need to break up the smooth edges of the path by adding threads. This part is where the ripping can get fun and creative.
Zoom in cloth to the ripping area but not too close. Take the ' pick color' tool and pick a color right next to the ripped area.
Next, take the 'brush' tool and set its pixel size to very low, preferably 1-2 pixels depending on your picture's resolution.
Add the tattered threads where needed, occasionally just tracing the rip's edge to break up it's smooth lining. It's an art to find the right balance on how much threads to put in and should vary by clothing type.
NOTES:
1. Make sure you make the threads look natural and follow the contours of the body.
2. Readjust your color for the color picker every so often because the color won't stay consistent.
3. Symmetry kills good ripping. Ripping is never symmetrical. It is chaotic and spontaneous. So go with the flow and don't make your rips and threads look like a synchronized swimming team. For some examples of how awesome ripping can look in 2-D, check out Readyart's comics. I think he's the master of clothes ripping at the moment in my honest opinion [link]