These charming valentines are easy enough for children of any age to make. When working with younger children, do all of the cutting yourself, even if you're only using scissors; make sure to keep utility knives out of the reach of children of any age.
Martha Stewart Living Television
Fold a piece of construction paper into quadrants. Unfold.
Drawing freehand or using a template, sketch a heart on the lower-left-hand quadrant of the paper. Cut out the heart.
Position the image or piece of decorative paper so it will be centered inside the heart-cutout panel once the card is folded. Cut the image or paper a bit smaller than the panel. Refold the construction paper so that the heart cutout becomes the front panel of the card. Lift up front panel to reveal under panel (this will be the left-hand side of the card's interior).
Glue the image or decorative paper to the under panel. Let dry, then write a Valentine's Day message inside.