Draw a sketch or landscape.For a card you might draw a Christmas tree or for a birthday card a big cake
After your sketch is ready keep it aside.Now select the colors you would like to fill in them.Here instead of colors we will use bits of papers.Suppose you have drawn a tree.Now tear a page that has green shades.Put your tip of the thumb on paper and tear it into bits.Keep tearing bits of green shades enough to fill up the tree.If there are clouds.Tear bits of blue paper and you might mix different shades of blue.They need not be neat.The beauty of this painting lies in different shapes of the paper and that too showing the torn white edges.
After you are done apply glue on their back and stick them on the part where you find it suitable.Example:Light green bits for tree and dark green for grass.
keep filling the whole picture until you are done.
let it dry.you may cover it with transparent plastic or use it for cards.
Above is an image of the painting I made.Its called magazine art also.