How to Make a Box Out of a Card

From Sherri Osborn, former About.com Guide

Use the picture as a guide to draw lines on each of your greeting card pieces.

Using a ruler and pen, you connect each of marks you made on the short edges of the card.

Note that the marks you made 3/4" from the corner on the long side of the card are not connected. Line up a ruler along those marks and draw a line from one line to another, not going all of the way to the edge of the card.

Finally, use the ruler to connect the second marks you made on each of the long edges.