I recently learned how to do this from my demo and I loved it. Faux Tearing is so easy to do and it comes in handy when you do not have a lot of cardstock in a certain shade or hue.
Ink to match
paper/cardstock to rip
Fold cardstock base in half and decide which way the card is going to go, vertical or horizontal.
Take your piece of paper or cardstock and rip it in half, making sure that there are some curves in the paper.
Place your ripped cardstock on top of your card base so that the part of the card showing is where the ink will go.
Ink up your brayer.
Hold down the white paper and run your brayer over the base card. You will have to reink it several times to get full coverage.
Finish your card. Here are two examples.