Trim paper down to 8.5x11 and print out the template (if using a laser printer - if using an ink jet printer, do the watercoloring before printing). Lay a gallon size ziplock bag next to your paper. Scribble on the ziplock bag with a few different colors of markers in the upper left quarter of the bag. Spray the bag with water until the ink beads up.
Flip the bag over onto the top right quarter of your paper. Use your fingertips (not nails) to blend the ink, then peel away the bag. Use a paper towel to clean up any ink that is running off the paper. You can also dab at your design with a paper towel if it seems extremely wet, or link the colors are blending too much.
Repeat the watercolor effect on the lower left quarter of the paper (you may or may not need to apply more ink and water to the bag before doing so).
Allow your paper to dry completely before continuing. You may also want to leave the paper between two heavy books overnight to flatten it out before folding the card. If you are using an ink jet printer, print the template onto the card after it's completely dry.
To fold the card: Keeping the decorated side out, fold the paper in half lengthwise, then in half widthwise.
Cut and discard the bottom right quarter of the paper. Also cut along the line on the bottom left and discard that portion as well.
Flip the card over, and fold up the flap on the right. Fold it in along the diagonal dashed line, then place adhesive on either side of the flap to create a pocket for the gift card.